Research

Recent projects undertaken at NTU

· Capturing Waste with Waste: Continuous Carbon Capture Using Highly Efficient Sorbents Derived from Incineration Ashes (New)

· “Breaking the Ground” in Semakau Landfill: Technological Solutions for Site Investigation and Material Reuse (new)

· Clean Syngas from Waste for Electricity and Chemicals (new)

· Development of an In-line Pre-formed Chloramine System for Biofouling Control in Seawater Reverse Osmosis Desalination Process (new)

· Long-Term Environmental Behavior for Treated Incineration Bottom Ash

· Investigation and Optimisation of Ozone Ceramic Membrane Process

· Improving Photocatalysts to Recycle Microplastics to Fuels by Artificial Intelligence

· Zero-Liquid Discharge from Water Reclamation through Hybrid Multiplex Catalytic Oxidation Process

· Advanced Combustion and Corrosion Control System for Steam Boilers in WtE Gasification Plants

· Nitrogen-Doped TIO₂-Activated Carbon (AC) Composite for Adsorptive Photocatalytic Oxidation-Reduction of Refractory Organic Substances Under Solar Irradiation in Water Purification

· Controlled Synthesis of Catalytic Polyoxometalates for the Removal of Phenol from Waste Water

· Gasification-based Syngas Upgrading and Purification System for Enhanced Power Generation

· A Novel Approach to Reutilize Incineration Bottom Ash (IBA) for Civil Engineering Applications: IBA Aerated Concrete

· Effective Techniques for Quick Response to Oil Spillage on Singapore Roads

· Sustainable Materials: Green Avenues Towards High Value Products

· Use of Copper Slag as a Land Reclamation Fill Material in Singapore

Total research grant

My total research grant received to date as Principal Investigator is S$6.5 millions (US$5.0 millions). In addition, I have also involved as a co-Principal Investigator of several projects which received a total research grant of S$18 millions.

R&D projects for community improvement

General summary of my research fields

My research encompasses both practical applications of environmental technologies and fundamental studies of process mechanisms. My core research areas of interest focus on advanced oxidation processes for water and wastewater treatment, developing innovative treatment technologies for water and soil pollution controls, developing nanomaterials for environmental applications, waste-to-energy and waste-to-materials. My research approach couples experimental investigations with use of geochemical models, statistical tools, and advanced analytical equipment for analysis and interpretation of the results. Brief summaries of my research projects and the representative publications are listed below.

Advanced oxidation processes for water and wastewater treatment

I have over 15 years of research track records in redox technologies for surface water, wastewater and groundwater treatment. For the oxidation technologies, my research activities cover sulfate-radical based advanced oxidation process or SR-AOP (homogeneous and heterogeneous), UV-based AOP (homogeneous and heterogeneous), Fenton processes (heterogeneous), photocatalysis (heterogeneous), electrochemical oxidation, and sonochemical oxidation, and hybrid AOPs. On SR-AOP, my group has made significant contribution to the scientific community in terms of advancing the understanding of the mechanisms of the heterogeneous SR-AOP with metal oxides (monometallic oxide and bimetallic oxides) and carbonaceous materials as catalysts to activate peroxymonosulfate and peroxydisulfate. We have discussed our works in our numerous scientific papers and 3 critical reviews in the top journals. Specifically, we have provided insights into the radical and non-radical reaction pathways associated with transformation and mineralization of a wide range of organic emerging micropollutants such as antibiotics, cytostatic drugs, bisphenol A and industrial chemicals (Oh et al. 2016, Chen et al. 2018). On the homogeneous SR-AOP, our group is among the leading contributor to mitigation strategy for controlling iodinated disinfection by-products such as iodinated trihalomethanes and iodoacids in RO water (Xiao et al. 2015, 2016). Our group also developed composite catalytic materials which comprise mixed metal oxides, bimetallic oxides, and catalyst-nanocarbon composites that exhibit multifunctional properties such as combined catalysis, adsorption-promoted catalysis, “switchable” catalysis, etc. Our iron-based catalytic composites can function as Fenton catalyst, photo-Fenton catalyst and photocatalyst, such that their applications can be switched over the day/night cycle (Hu et al. 2014, 2015). When irradiated with sunlight, they trigger sunlight-driven photocatalytic redox degradation of organic pollutants without any chemical addition. The materials can be recovered from the treated water using magnet. We have also developed a hybrid TiO2-activated carbon composites, which can be used as solar-driven photocatalyst (Yap et al., 2011) or solar-regenerable activate carbon (Yap and Lim 2012). This invention has been approved for PCT filing (PCT/SG2014/000273) as a recognition of our intellectual property.

1.	Bao Y., Oh W.D., Lim T.T., Wang R., Webster R.D., Hu X. (2019). Elucidation of stoichiometric efficiency, radical generation and transformation pathway during catalytically oxidation of sulfamethoxazole via peroxymonosulfate activation. Water Research 151, 64-74.
2.	Oh W.D., Lim T.T. (2019). Design and application of heterogeneous catalysts as peroxydisulfate activator for organics removal: An overview. Chemical Engineering Journal 358, 110-133.
3.	Oh W.D., Chang V.W.C., Lim T.T. (2019). A comprehensive performance evaluation of heterogeneous Bi₂Fe₄O₉/peroxymonosulfate system for sulfamethoxazole degradation. Environmental Science and Pollution Research 26, 1026-1035.
4.	Zhang Y., Lim T.T.* (2018). Chapter 12 Photodegradation of cytostatic drugs in low-pressure UV photoreactor through direct and indirect pathways. In Fate and Effects of Cytostatic Pharmaceuticals in the Environment. Eds. Heath E., Filipič M., Kosjek T., Isidori M. In press. Springer.
5.	Bao Y., Oh W.D., Lim T.T., Wang R., Webster R.W., Hu X. (2018). Surface-nucleated heterogeneous growth of zeolitic imidazolate framework-A unique precursor towards catalytic ceramic membranes: synthesis, characterization and organics degradation. Chemical Engineering Journal 353, 69-79.
6.	Bao Y., Lim T.T., Wang R., Webster R.D., Hu X.* (2018). Urea-assisted one-step synthesis of cobalt ferrite impregnated ceramic membrane for sulfamethoxazole degradation via peroxymonosulfate activation. Chemical Engineering Journal 343, 737-747.
7.	Chen X., Oh W.D., Hu Z.T., Sun Y.M., Webster R.D., Li S.Z., Lim T.T.* (2018). Enhancing sulfacetamide degradation by peroxymonosulfate activation with N-doped graphene produced through delicately-controlled nitrogen functionalization via tweaking thermal annealing processes. Applied Catalysis B: Environmental 225, 243–257.
8.	Hu Z.T., Oh W.D., Liu Y., Yang E.H., Lim T.T. (2018). Controllable mullite bismuth ferrite micro/nanostructures with multifarious catalytic activities for switchable/hybrid catalytic degradation processes. Journal of Colloid and Interface Science 509, 502-514.
9.	Oh W.D., Dong Z., Goei R., Lim T.T.* (2017). Surface-active bismuth ferrite as superior peroxymonosulfate activator for aqueous sulfamethoxazole removal: Performance, mechanism and quantification of sulfate radical. Journal of Hazardous Materials 325, 71-81.
10.	Zhang Y., Zhang J., Xiao Y., Chang V.W.C., Lim T.T.* (2017). Direct and indirect photodegradation pathways of cytostatic drugs under UV germicidal irradiation: process kinetics and influences of water matrix species and oxidant dosing. Journal of Hazardous Materials 324, 481-488.
11.	Oh W.D., Dong Z., Lim T.T.* (2017). Hierarchically-structured Co–CuBi₂O₄and Cu–CuBi₂O₄for sulfanilamide removal via peroxymonosulfate activation. Catalysis Today 280, 2-7.
12.	Zhang Y., Xiao Y., Zhang J., Chang V.W.C., Lim T.T.* (2017). Degradation of cyclophosphamide and 5-fluorouracil in water using UV and UV/H₂O₂: kinetics investigation, pathways and energetic analysis. Journal of Environmental Chemical Engineering 5(1), 1133-1139.
13.	Wu W., Huang Z.H., Hu Z.-T., He C., Lim T.T.* (2017). High performance duplex-structured SnO₂ anode modified by SnO₂-Sb-CNT composite for bisphenol A removal: Electrochemical oxidation enhanced by adsorption. Separation and Purification Technology 179, 25-35.
14.	Oh W.D., Chang V.W.C., Hu Z.T., Goei R., Lim T.T.** (2017). Enhancing the catalytic activity of g-C₃N₄ through Me doping (Me = Cu, Co and Fe) for selective sulfathiazole degradation via redox-based advanced oxidation process. Chemical Engineering Journal 323, 260-269.
15.	Zhang Y., Zhang J., Xiao Y., Chang V.W.C., Lim T.T.* (2016). Kinetic and mechanistic investigation of azathioprine degradation in water by UV, UV/H₂O₂ and UV/persulfate. Chemical Engineering Journal 302, 526–534.
16.	Oh W.D., Dong Z., Lim T.T.* (2016). Generation of sulfate radical through heterogeneous catalysis for organic contaminants removal: Current development, challenges and prospects. Applied Catalysis B: Environmental 194, 169–201.
17.	Xiao Y., Zhang L., Zhang W., Lim K.Y., Webster R.D., Lim T.T.* (2016). Comparative evaluation of iodoacids removal by UV/persulfate and UV/H₂O₂ processes. Water Research. 102, 629-639.
18.	Wu W., Huang Z.H., Lim T.T.* (2016). A comparative study on electrochemical oxidation of bisphenol A by boron-doped diamond anode and modified SnO₂-Sb anodes: influencing parameters and reaction pathways. Journal of Environmental Chemical Engineering 4, 2807-2815.
19.	Hu Z.T., Chen Z., Goei R., Wu W., Lim T.T.* (2016). Magnetically recyclable Bi/Fe-based hierarchical nanostructures via self-assembly for environmental decontamination. Nanoscale 8, 12736-12746.
20.	Oh W.D., Lua S.K., Dong Z., Lim T.T.* (2016). Fabrication of three-dimensional hierarchically-structured CuBi₂O₄ composites via kinetic control for versatile application in water treatment. Nanoscale 8, 2046 – 2054.
21.	Lua S.K., Oh W.D., Zhang L.Z., Yao L., Lim T.T., Dong Z.* (2015). A molybdovanadophosphate-based surfactant encapsulated heteropolyanion with multi-lamellar nano-structure for catalytic wet air oxidation of organic pollutant under ambient conditions. RSC Advances 5 (115), pp. 94743-94751.
22.	Oh W.D., Dong Z., Hu Z., Lim T.T.* (2015). A novel quasi-cubic CuFe₂O₄–Fe₂O₃ prepared at low temperature for enhanced oxidation of bisphenol A via peroxymonosulfate activation. Journal of Materials Chemistry A 3, 22208-22217.
23.	Hu Z.T., Lua S.K., Lim T.T.* (2015). Cuboid-like Bi₂Fe₄O₉/Ag with graphene-wrapping tribrid composite with superior capability for environmental decontamination: Nanoscaled material design and visible-light-driven multifunctional catalyst. ACS Sustainable Chemistry & Engineering 3 (11), pp. 2726-2736.
24.	Hu Z.T., Lua S.K., Yan X., Lim T.T.* (2015). Nanostructured hexahedron of bismuth ferrite clusters: delicate synthesis processes and an efficient multiplex catalyst for organic pollutant degradation. RSC Advances 5, 86891–86900.
25.	Oh W.D., Lua S.K., Dong Z., Lim T.T.* (2015). A novel three-dimensional spherical CuBi₂O₄ nanocolumn arrays with persulfate and peroxymonosulfate activation functionalities for 1H-benzotriazole removal. Nanoscale 7(17), 8149-8158.
26.	Wu W., Huang Z., Lim T.T.* (2015). Enhanced electrochemical oxidation of phenol using hydrophobic TiO₂-NTs/SnO₂-Sb-PTFE electrode prepared by pulse electrodeposition. RSC Advances 5, 32245-32255.
27.	Xiao Y., Zhang L., Yue J., Webster R.D., Lim T.T.* (2015). Kinetic modeling and energy efficiency of UV/H2O2 treatment of iodinated trihalomethanes Water Research 75, 259-269.
28.	Oh W.D., Lua S.K., Dong Z., Lim T.T.* (2015). Performance of magnetic activated carbon composite as peroxymonosulfate activator and regenerable adsorbent via sulfate radical-mediated oxidation processes. Journal of Hazardous Materials 284(2), 1-9.
29.	Oh W.D., Lua S.K., Dong Z., Lim T.T.* (2014). High surface area DPA-hematite for efficient detoxification of bisphenol A via peroxymonosulfate activation. Journal of Materials Chemistry A 38, 15836-15845.
30.	Hu Z-T, Chen B., Lim T.T.* (2014). Single-crystalline Bi₂Fe₄O₉ synthesized by low-temperature co-precipitation: Performance as photo- and Fenton catalysts. RSC Advances 4, 27820–27829.
31.	Zhou T., Wu X., Mao J., Zhang Y., Lim T.T.* (2014). Rapid degradation of sulfonamides in a novel heterogeneous sonophotochemical magnetite-catalyzed Fenton-like (US/UV/Fe₃O₄/Oxalate) system. Applied Catalysis B: Environmental 160-161, 325-334.
32.	Wu W., Huang Z., Lim T.T.* (2014). Recent development of mixed metal oxide anodes for electrochemical oxidation of organic pollutants in water. Applied Catalysis A: General 480, 58-78.
33.	Xiao Y., Fan R., Zhang L., Yue J., Webster R.D., Lim T.T.* (2014). Photodegradation of iodinated trihalomethanes in aqueous solution by UV 254 irradiation. Water Research 49, 275-285.
34.	Zhou T., Wu X., Zhang Y., Li J., Lim T.T. (2013). Synergistic catalytic degradation of antibiotic sulfamethazine in a heterogeneous sonophotolytic goethite/oxalate Fenton-like system. Applied Catalysis B: Environmental 136– 137, 294–301.
35.	Yap P.S., Lim T.T.* (2012). Solar regeneration of powdered activated carbon impregnated with visible-light responsive photocatalyst: factors affecting performances and predictive model. Water Research 46, 3054-3064.
36.	Zhou T., Lim T.T., Wu X. (2011). Sonophotolytic degradation of azo dye reactive black 5 in a ultrasound/UV/ferric system and the roles of different organic ligands. Water Research 45(9), 2915-2924.
37.	Zhou T., Lim T.T.*, Chin S.S., Fane A.G. (2011). Treatment of organics in reverse osmosis concentrate from a municipal wastewater reclamation plant: Feasibility test of advanced oxidation processes with/without pretreatment. Chemical Engineering Journal 166, 932-939.
38.	Zhou T., Lu X., Lim T.T.*, Li Y., Wong F.S. (2010). Degradation of chlorophenols (CPs) in an ultrasound-irradiated Fenton-like system at ambient circumstance: The QSPR (quantitative structure–property relationship) study. Chemical Engineering Journal 156, 347–352.
39.	Zhou T., Lim T.T., Li Y., Lu X., and Wong F.S. (2010). The role and fate of EDTA in ultrasound-enhanced zero-valent iron / air system. Chemosphere 78, 576–582.
40.	Zhou T., Lim T.T.*, Lu X., Li Y., Wong F.S. (2009). Simultaneous degradation of 4CP and EDTA in a heterogeneous ultrasound/Fenton like system at ambient circumstance. Separation and Purification Technology 68 (3), 367-374.

Photocatalysis
1.	Bao Y., Lim T.T., Goei R., Zhong Z., Wang R., Hu X.* (2018). One-step construction of heterostructured metal-organics@Bi₂O₃ with improved photoinduced charge transfer and enhanced activity in photocatalytic degradation of sulfamethoxazole under solar light irradiation. Chemosphere 205, 396-403.
2.	Hu Z.-T., Liang Y.N., Zhao J., Zhang Y., Yang E.-H., Chen J., Lim T.T.** (2018). Ultra-effective integrated technologies for water disinfection with a novel 0D-2D-3D nanostructured rGO-AgNP/Bi₂Fe₄O₉ composite. Applied Catalysis B: Environmental 227, 548-556.
3.	Oh W.D., Lok L.W., Veksha A., Giannis A., Lim T.T. (2018). Enhanced photocatalytic degradation of bisphenol A with Ag-decorated S-doped g-C₃N₄ under solar irradiation: Performance and mechanistic studies. Chemical Engineering Journal 333, 739-749.
4.	Nie L, Liu G., Xie J., Lim T.T., Armatas G.S., Xu R., Zhang Q.* (2017). Syntheses, crystal structures, and photocatalytic properties of two ammonium-directed Ag−Sb−S complexes. Inorganic Chemistry Frontier 4, 954-959.
5.	Bao Y., Lim T.T., Zhong Z., Wang R., Hu X.* (2017). Acetic acid-assisted fabrication of hierarchical flower-like Bi₂O₃ for photocatalytic degradation of sulfamethoxazole and rhodamine B under solar irradiation. Journal of Colloid and Interface Science 505(1) 489-499.
6.	Hu Z.T., Chen Z., Goei R., Wu W., Lim T.T.* (2016). Magnetically recyclable Bi/Fe-based hierarchical nanostructures via self-assembly for environmental decontamination. Nanoscale 8, 12736-12746.
7.	Chen Z.* and Lim T.T. (2016). Chapter 4 Nanostructured Catalytic and Adsorbent Materials for Water Remediation. In 50 years of Materials Science in Singapore. Eds. Boey F., Chowdari B.V.R., Venkatraman S.S. World Scientific Publishing Ltd., pp 75-111.
8.	Yu S., Liu J., Zhu W., Hu Z., Lim T.T., Yan X.* (2015). Facile room-temperature synthesis of carboxylated graphene oxide-copper sulfide nanocomposite with high photodegradation and disinfection activities under solar light irradiation. Scientific Reports 5, 16369. doi:10.1038/srep16369.
9.	Hu Z.T., Lua S.K., Yan X., Lim T.T.* (2015). Nanostructured hexahedron of bismuth ferrite clusters: delicate synthesis processes and an efficient multiplex catalyst for organic pollutant degradation. RSC Advances 5, 86891–86900.
10.	Hu Z.T., Lua S.K., Lim T.T.* (2015). Cuboid-like Bi₂Fe₄O₉/Ag with graphene-wrapping tribrid composite with superior capability for environmental decontamination: Nanoscaled material design and visible-light-driven multifunctional catalyst. ACS Sustainable Chemistry & Engineering 3 (11), pp. 2726-2736.
11.	Hu Z.T., Liu J., Yan X., Oh W.D., Lim T.T.* (2015). Low-temperature synthesis of graphene/Bi₂Fe₄O₉ composite for synergistic adsorption-photocatalytic degradation of hydrophobic pollutant under solar irradiation. Chemical Engineering Journal 262, 1022–1032.
12.	Goei R., Lim T.T.* (2014). Ag-decorated TiO₂ photocatalytic membrane with hierarchical architecture: photocatalytic and anti-bacterial activities. Water Research 59, 207–218.
13.	Hu Z-T, Chen B., Lim T.T.* (2014). Single-crystalline Bi₂Fe₄O₉ synthesized by low-temperature co-precipitation: Performance as photo- and Fenton catalysts. RSC Advances 4, 27820–27829.
14.	Goei R., Lim T.T.* (2014). Asymmetric TiO₂ hybrid photocatalytic ceramic membrane with porosity gradient: Effect of structure directing agent on the resulting membranes architecture and performances. Ceramics International 40, 6747-6757.
15.	Ronn G., Dong Z.L., Lim T.T.* (2013). High-permeability Pluronic-based TiO₂ hybrid photocatalytic membrane with hierarchical porosity: fabrication, characterizations and performances. Chemical Engineering Journal 228, 1030-1039.
16.	Wang P., Fane A. G., Lim T.T.* (2013). Evaluation of a submerged membrane vis–LED photoreactor (sMPR) for carbamazepine degradation and TiO₂ separation. Chemical Engineering Journal 215-216, 240–251.
17.	Han Z., Chang V.W., Wang X., Lim T.T.*, Lynn H. (2013). Experimental study on visible-light induced photocatalytic oxidation of gaseous formaldehyde by polyester fiber supported photocatalysts. Chemical Engineering Journal 218, 9-18.
18.	Wang X., Lim T.T.* (2013). Highly efficient and stable Ag-AgBr/TiO₂ composites for destruction of E. coli under visible light irradiation. Water Research 47 (12), pp. 4148-4158.
19.	Wang P., Tang Y., Dong Z., Chen Z., Lim T.T.* (2013). Ag–AgBr/TiO₂/RGO nanocomposite for visible–light photocatalytic degradation of penicillin G. Journal of Materials Chemistry A 1, 4718–4727.
20.	Yap P.S., Cheah Y.L., Srinivasan M., Lim T.T.* (2012). Bimodal N-doped P25-T_iO₂/AC composite: Preparation, characterization, physical stability, and synergistic adsorptive-solar photocatalytic removal of sulfamethazine. Applied Catalysis A: General 427–428, 125-136.
21.	Wang X., Tang Y., Chen Z., Lim T.T.* (2012). Highly stable heterostructured Ag-AgBr/TiO₂ composite: A bifunctional visible-light active photocatalyst for destruction of ibuprofen and bacteria. Journal of Materials Chemistry 22(43), 23149-23158.
22.	Hou D.X., Goei R., Wang X, Wang P., Lim T.T.* (2012). Preparation of carbon-sensitized and Fe-Er codoped TiO₂ with response surface methodology for bisphenol A photocatalytic degradation under visible-light irradiation. Applied Catalysis B: Environmental, 126, 121-133.
23.	Yap P.S., Lim T.T.* (2012). Solar regeneration of powdered activated carbon impregnated with visible-light responsive photocatalyst: factors affecting performances and predictive model. Water Research 46, 3054-3064.
24.	Tang Y., Wee P., Lai Y., Wang X., Gong D., Kanhere P.D., Lim T.T., Dong Z., Chen Z.* (2012). Hierarchical TiO₂ Nanoflakes and nanoparticles hybrid structure for improved photocatalytic activity. Journal of Physical Chemistry C 116 (4), 2772–2780.
25.	Wang P., Lim T.T.* (2012). Membrane vis-LED photoreactor for simultaneous penicillin G degradation and TiO₂ separation. Water Research 46(6), 1825-1837.
26.	Hou D., Feng L., Zhang J., Dong S., Zhou D., Lim T.T.* (2012). Preparation, characterization and performance of a novel visible light responsive spherical activated carbon-supported and Er^3+:YFeO₃-doped TiO₂ photocatalyst. Journal of Hazardous Materials 199-200, 301-308.
27.	Wang X.P., Tang Y, Leiw M.Y., Lim T.T.* (2011). Solvothermal synthesis of Fe-C codoped TiO₂ nanoparticles for visible-light photocatalytic removal of emerging organic contaminants in water. Applied Catalysis A: General 409–410, 257– 266.
28.	Wang P., Zhou T., Wang R., Lim T.T.* (2011). Carbon-sensitized and nitrogen-doped TiO₂ for photocatalytic degradation of sulfanilamide under visible-light irradiation. Water Research 45, 5015-5026.
29.	Gao B., Yap P.S., Lim T.M., Lim T.T. (2011). Adsorption-photocatalytic degradation of acid red 88 by supported TiO₂ : Effect of activated carbon support and aqueous anions. Chemical Engineering Journal 171, 1098-1107.
30.	Wang X.P., Lim T.T.* (2011). Effect of hexamethylenetetramine on the visible-light photocatalytic activity of C-N codoped TiO₂ for bisphenol A degradation: evaluation of photocatalytic mechanism and solution toxicity. Applied Catalysis A: General 399, 233-241.
31.	Wang P., Yap P.S., Lim T.T.* (2011). C-N-S tridoped TiO₂ for photocatalytic degradation of tetracycline under visible-light irradiation. Applied Catalysis A: General 399, 252–261.
32.	Yap P.S., Lim T.T.* (2011). Effect of aqueous matrix species on synergistic removal of bisphenol-A under solar irradiation using nitrogen-doped TiO₂/AC composite. Applied Catalysis B: Environmental 101, 709-717.
33.	Yap P.S., Lim T.T.*, Srinivasan M. (2011). Nitrogen-doped TiO₂/AC bi-functional composite prepared by two-stage calcination for enhanced synergistic removal of hydrophobic pollutant using solar irradiation. Catalysis Today 161, 46-52.
34.	Wang X.P., Lim T.T.* (2010). Solvothermal synthesis of C-N codoped TiO₂ and photocatalytic evaluation for bisphenol A degradation using a visible-light irradiated LED photoreactor. Applied Catalysis B: Environmental. 100, 355-364.
35.	Lim T.T.*, Yap P.S., Srinivasan M., Fane A.G. (2010). TiO₂/AC composites for synergistic adsorption-photocatalysis processes: present challenges and further developments for water treatment and reclamation. Critical Reviews in Environmental Science and Technology 41(13), 1173 - 1230.
36.	Subagio D.P., Srinivasan M., Lim M., Lim T.T. (2010). Photocatalytic degradation of Bisphenol-A by nitrogen-doped TiO₂ hollow sphere in a Vis-LED photoreactor. Applied Catalysis B: Environmental 95, 414–422.
37.	Yap P.S., Lim T.T.*, Lim M., Srinivasan M. (2010). Synthesis and characterization of nitrogen-doped TiO₂/AC composite for the adsorption-photocatalytic degradation of aqueous bisphenol-A using solar light. Catalysis Today 151, 8–13.
38.	Gao B., Lim T.M., Subagio D.P., Lim T.T. (2010). Zr-doped TiO₂ for enhanced photocatalytic degradation of bisphenol A. Applied Catalysis A: General 375(1), 107-115.

Environmental nanomaterials for water/air decontamination

*Catalytic ceramic membrane for removing recalcitrant organics* Over the last 10 years, my group has advanced the research of coupling catalytic oxidation and membrane separation process. The synergistic processes were enabled through our catalytic ceramic membrane research. We developed three types of such hybrid membranes: (1) photocatalytic membrane, (2) catalytic sulfate-radical oxidation membrane, and (3) catalytic ozonation ceramic membrane. One of our inventions, Ag-decorated photocatalytic TiO2-coated alumina membrane, has three functionalities: antibacterial and antibiofouling property, photocatalytic, and separation with pore sizes down to 4 nm (Goei and Lim 2014).
1.	Bao Y., Oh W.D., Lim T.T., Wang R., Webster R.W., Hu X. (2018). Surface-nucleated heterogeneous growth of zeolitic imidazolate framework-A unique precursor towards catalytic ceramic membranes: synthesis, characterization and organics degradation. Chemical Engineering Journal 353, 69-79.
2.	Bao Y., Lim T.T., Wang R., Webster R.D., Hu X.* (2018). Urea-assisted one-step synthesis of cobalt ferrite impregnated ceramic membrane for sulfamethoxazole degradation via peroxymonosulfate activation. Chemical Engineering Journal 343, 737-747.
3.	Lim T.T.* and Goei R. (2016). Chapter 5 Combined Photocatalysis-Separation Processes for Water Treatment using Hybrid Photocatalytic Membrane Reactors. In Photocatalysis: Applications. Eds. Dionysiou D. D., Li Puma G., J. Ye, Schneider J., Bahnemann D.. Royal Society of Chemistry, pp 130-156.
4.	Goei R., Lim T.T.* (2014). Ag-decorated TiO₂ photocatalytic membrane with hierarchical architecture: photocatalytic and anti-bacterial activities. Water Research 59, 207–218.
5.	Goei R., Lim T.T.* (2014). Asymmetric TiO₂ hybrid photocatalytic ceramic membrane with porosity gradient: Effect of structure directing agent on the resulting membranes architecture and performances. Ceramics International 40, 6747-6757.
6.	Ronn G., Dong Z.L., Lim T.T.* (2013). High-permeability Pluronic-based TiO₂ hybrid photocatalytic membrane with hierarchical porosity: fabrication, characterizations and performances. Chemical Engineering Journal 228, 1030-1039.

*Zerovalent metal particles*
1.	Kim H.S., Kim T., Ahn J.Y., Hwang K.Y., Park J.Y., Lim T.T., Hwang I.* (2012). Aging characteristics and reactivity of two types of nanoscale zero-valent iron particles (Fe^BH and Fe^H2) in nitrate reduction. Chemical Engineering Journal 197, 16–23.
2.	Zhou T., Li Y., Lim T.T.* (2010). Catalytic hydrodechlorination of chlorophenols by Pd/Fe nanoparticles: Comparisons with other bimetallic systems, kinetics and mechanism. Separation and Purification Technology 76, 206-214.
3.	Lim T.T.* and Zhu B.W. (2009). Chapter 14: Practical applications of bimetallic nanoiron particles for reductive dehalogenation of haloorganics: prospects and challenges. In Environmental Applications of Nanoscale and Microscale Reactive Metal Particles. Eds. K.M. Carvalho-Knighton and C. L. Geiger, ACS Symposium Series, Vol. 1027, American Chemical Society, USA, pp 245-261.
4.	Feng J., Zhu B.W., Lim T.T.* (2008). Reduction of chlorinated methanes with nano-scale Fe particles: Effects of amphiphiles on the dechlorination reaction and two-parameter regression for kinetic prediction. Chemosphere 73, 1817–1823.
5.	*Lim T.T.,** Zhu B.W. (2008). Effects of anions on the kinetics and reactivity of nanoscale Pd/Fe in trichlorobenzene dechlorination. Chemosphere 73, 1471–1477.
6.	Zhu B.W., *Lim T.T.,** Feng J. (2008). Influences of amphiphiles on dechlorination of a trichlorobenzene by nanoscale Pd/Fe: Adsorption, reaction kinetics, and interfacial interactions. Environmental Science & Technology 42, 4513–4519.
7.	Zhu B.W., Lim T.T.* (2007). Catalytic reduction of chlorobenzenes with Pd/Fe nanoparticles: reactive sites, catalyst stability, particle ageing and regeneration. Environmental Science & Technology 41, 7523-7529.
8.	Lim T.T.*, Feng J., Zhu B.W. (2007). Kinetic and mechanistic examinations of reductive transformation pathways of brominated methanes with nano-scale Fe and Ni/Fe particles. Water Research 41, 875-883.
9.	Feng J., Lim T.T.* (2006). Iron-mediated reduction rates and pathways of halogenated methanes with nanoscale Pd/Fe: Analysis of linear free energy relationship. Chemosphere. Chemosphere 66(9), 1765-1774.
10.	Zhu B.W., *Lim T.T.,** Feng J. (2006). Reductive dechlorination of 1,2,4-trichlorobenzene with palladized nanoscale Fe⁰ particles supported on chitosan and silica. Chemosphere, 65(7), 1137-1145.
11.	Feng J., Lim T.T.* (2005). Pathways and kinetics of carbon tetrachloride and chloroform reductions by nano-scale Fe and Fe/Ni particles: comparison with commercial micro-scale Fe and Zn. Chemosphere 59(9), 1267-1277.
*Nanosorbents*
1.	Oh W.D., Lei J., Veksha A., Giannis A., Chan W.P., Lisak G., Lim T.T.** (2018). Ni-Zn-based nanocomposite loaded on cordierite-mullite honeycomb for syngas desulfurization: Performance evaluation and regeneration studies. Chemical Engineering Journal 351, 230-239.
2.	Wu M., Chang B., Lim T.T., Oh W.D., Lei J., Mi J. (2018). High-sulfur capacity and regenerable Zn-based sorbents derived from layered double hydroxide for hot coal gas desulfurization. Journal of Hazardous Materials 360, 391-401.
3.	Wu M., Shi L., Lim T.T., Veksha A., Yu F., Fan H., Mi J. (2018). Ordered mesoporous Zn-based supported sorbent synthesized by a new method for high-efficiency desulfurization of hot coal gas. Chemical Engineering Journal 353, 273-287.
4.	Oh W.D., Lei J., Veksha A., Giannis A., Lisak G., Chang V.W.C., Hu X., Lim T.T. (2018). Influence of surface morphology on the performance of nanostructured ZnO-loaded ceramic honeycomb for syngas desulfurization. Fuel 211C, 591-599.
5.	Loo S.L., Lim T.T., Krantz W.B., Fane A.G.*, Hu X. (2015). Potential evaluation and perspectives on using sponge-like superabsorbent cryogels for onsite water treatment in emergencies. Desalination and Water Treatment 53, 1506-1515.
6.	Loo S.L., Fane A.G., Lim T.T., Krantz W.B., Liang Y.N., Liu X., Hu X. (2013). Superabsorbent cryogels decorated with silver nanoparticles as a novel water technology for point-of-use disinfection, Environmental Science & Technology 47(16), 9363-9371.
7.	Chen C. P., Wang P. H., Lim T.T., Liu L. H., Liu S. M., Xu R.* (2013). A facile synthesis of monodispersed hierarchical layered double hydroxide on silica spheres for efficient removal of pharmaceuticals from water. Journal of Materials Chemistry A 1, 3877–3880.
8.	Loo S.L., Krantz W.B., Lim T.T., Fane A.G., Hu X. (2013). Design and synthesis of ice-templated PSA cryogels for water purification: Towards tailored morphology and properties. Soft Matter 9(1), 224–234.
9.	Wang B., Wu H., Yu L. Xu R., Lim T.T., Lou X.W.* (2012). Template-free formation of uniform urchin-like a-FeOOH hollow spheres with superior capability for water treatment. Advanced Materials 24(8), 1111-1116.
10.	Goh K.H., Lim T.T.* (2010). Influences of co-existing species on the sorption of toxic oxyanions from aqueous solution by nanocrystalline Mg/Al layered double hydroxide. Journal of Hazardous Materials 180, 401-408.
11.	Goh K.H., Lim T.T.*, Banas A., Dong Z.L. (2010). Sorption characteristics and mechanisms of oxyanions and oxyhalides having different molecular properties on Mg/Al layered double hydroxide nanoparticles. Journal of Hazardous Materials 179 (1-3), 818-827.
12.	Goh K.H., Lim T.T.*, Dong Z.L. (2010). Removal of arsenate from aqueous solution by nanocrystalline Mg/Al layered double hydroxide: sorption characteristics, prospects, and challenges. Water Science & Technology 61(6), 1411-1417.
13.	Goh K.H., Lim T.T.*, Dong Z.L. (2009). Enhanced arsenic removal by hydrothermally treated nanocrystalline Mg/Al layered double hydroxide with nitrate intercalation. Environmental Science & Technology 43, 2537–2543.
14.	Lim T.T.*, Goh K.H., Goei R., Dong Z.L. (2009). Mechanistic and thermodynamic studies of oxyanion sorption by various synthetic Mg/Al layered double hydroxides. Water Science & Technology 59(5), 1011-1017.
15.	Goh K.H., Lim T.T.*, Dong Z.L. (2008). Application of layered double hydroxides for removal of oxyanions: a review. Water Research 42, 1343 – 1368.

Water supply

1.	Hu Z.-T., Liang Y.N., Zhao J., Zhang Y., Yang E.-H., Chen J., Lim T.T.** (2018). Ultra-effective integrated technologies for water disinfection with a novel 0D-2D-3D nanostructured rGO-AgNP/Bi₂Fe₄O₉ composite. Applied Catalysis B: Environmental 227, 548-556.
2.	Xiao Y., Zhang L., Zhang W., Lim K.Y., Webster R.D., Lim T.T.* (2016). Comparative evaluation of iodoacids removal by UV/persulfate and UV/H₂O₂ processes. Water Research. 102, 629-639.
3.	Xiao Y., Zhang L., Yue J., Webster R.D., Lim T.T.* (2015). Kinetic modeling and energy efficiency of UV/H₂O₂ treatment of iodinated trihalomethanes Water Research 75, 259-269.
4.	Loo S.L., Krantz W.B., Fane A.G., Gao Y., Hu X., Lim T.T. (2015). Effect of synthesis routes on the properties and bactericidal activity of cryogels incorporated with silver nanoparticles. RSC Advances 5(55), 44626-44635.
5.	Loo S.L., Krantz W.B., Hu X., Fane A.G., Lim T.T. (2016). Impact of solution chemistry on the properties and bactericidal activity of silver nanoparticles decorated on superabsorbent cryogels. Journal of Colloid and Interface Science 461, 104–113.
6.	Loo S.L., Krantz W.B., Fane A.G., Gao Y., Lim T.T., Hu X. (2015). Bactericidal mechanisms revealed for rapid water disinfection by superabsorbent cryogels decorated with silver nanoparticles. Environmental Science & Technology 49(4), 2310-2318.
7.	Loo S.L., Lim T.T., Krantz W.B., Fane A.G.*, Hu X. (2015). Potential evaluation and perspectives on using sponge-like superabsorbent cryogels for onsite water treatment in emergencies. Desalination and Water Treatment 53, 1506-1515.
8.	Xiao Y., Fan R., Zhang L., Yue J., Webster R.D., Lim T.T.* (2014). Photodegradation of iodinated trihalomethanes in aqueous solution by UV 254 irradiation. Water Research 49, 275-285.
9.	Loo S.L., Fane A.G., Lim T.T., Krantz W.B., Liang Y.N., Liu X., Hu X. (2013). Superabsorbent cryogels decorated with silver nanoparticles as a novel water technology for point-of-use disinfection, Environmental Science & Technology 47(16), 9363-9371.
10.	Loo S.L., Krantz W.B., Lim T.T., Fane A.G., Hu X. (2013). Design and synthesis of ice-templated PSA cryogels for water purification: Towards tailored morphology and properties. Soft Matter 9(1), 224–234.
11.	Loo S.L., Fane A.G., Krantz W.B., Lim T.T. (2012). Emergency water supply: A review of potential technologies and selection criteria. Water Research 46, 3125-3151.
12.	Goh K.H., *Lim T.T.,** Chui P.C. (2008). Evaluation of the effect of dosage, pH and contact time on high-dose phosphate inhibition for copper corrosion control using response surface methodology (RSM). Corrosion Science 50, 918–927.

Waste treatment

*Waste-to-energy*
1.	Jia J., Veksha A., Lim T.T., Lisak G. (2020). In situ grown metallic nickel from X-Ni (X=La, Mg, Sr) oxides for converting plastics into carbon nanotubes: Influence of metal-support interaction. Journal of Cleaner Production. In press.
2.	Pan Z., Chan W.P., Oh W.D., Veksha A., Giannis A., Tamilselvam K.S.O., Lei J., Khairunnisa D., Wang H., Lisak G., Lim T.T. (2020). Regenerable Co-ZnO-based nanocomposites for high-temperature syngas desulfurization. Fuel Processing Technology 201, 106344.
3.	Chan W.P., Sofea A.M., Veksha A., Giannis A., Lim T.T., Lisak G. (2020). Analytical assessment of tar generated during gasification of municipal solid waste: distribution of GC-MS detectable tar compounds, undetectable tar residues and inorganic impurities. Fuel 268, 117348
4.	Pan Z., Chan W.P., Veksha A., Giannis A., Dou X., Wang H., LisakG., Lim T.T.** (2019). Thermodynamic analyses of synthetic natural gas production via municipal solid waste gasification, high-temperature water electrolysis and methanation. Energy Conversion and Management 202, 112160.
5.	Chan W.P., Veksha A., Lei X., Oh W.D., Dou X., Giannis A., Lisak G., Lim T.T.** (2019). A hot syngas purification system integrated with downdraft gasification of municipal solid waste. Applied Energy 237, 227-240.
6.	Dou X., Veksha A., Chan W.P., Oh W.D., Liang Y.N., Teoh F., Dara K., Giannis A., Lisak G., Lim T.T.** (2019). Poisoning effects of H₂S and HCl on the naphthalene steam reforming and water-gas shift activities of Ni and Fe catalysts. Fuel 241, 1008-1018.
7.	Chan W.P., Veksha A., Lei X., Oh W.D., Dou X., Giannis A., Lisak G., Lim T.T.* (2019). A novel real-time monitoring and control system for waste-to-energy gasification process employing differential temperature profiling of a downdraft gasifier. Journal of Environmental Management 234, 65-74.
8.	Veksha A., Giannis A., Yuan G., Tng J., Chan W.P., Chang V.W.C., Lisak G., Lim T.T. (2019). Distribution and modeling of tar compounds produced during downdraft gasification of municipal solid waste. Renewable Energy 136, 1294-1303.
9.	Oh W.D., Lei J., Veksha A., Giannis A., Chan W.P., Lisak G., Lim T.T. (2018). Ni-Zn-based nanocomposite loaded on cordierite-mullite honeycomb for syngas desulfurization: Performance evaluation and regeneration studies. Chemical Engineering Journal 351, 230-239.
10.	Veksha A., Giannis A., Oh W.D., Chang V.W.C., Lisak G., Lim T.T.** (2018), Catalytic activities and resistance to HCl poisoning of Ni-based catalysts during steam reforming of naphthalene. Applied Catalysis A: General 557, 25-38.
11.	Oh W.D., Lei J., Veksha A., Giannis A., Lisak G., Chang V.W.C., Hu X., Lim T.T. (2018). Influence of surface morphology on the performance of nanostructured ZnO-loaded ceramic honeycomb for syngas desulfurization. Fuel 211C, 591-599.
*Waste-to-materials*
1.	Chanaka Udayanga W.D., Veksha A., Giannis A., Lisak G., Lim T.T.* (2019). Effects of sewage sludge organic and inorganic constituents on the properties of pyrolysis products. Energy Conversion and Management 196， 1410-1419.
2.	Chanaka Udayanga W.D., Veksha A., Giannis A., Lim T.T.* (2019). Pyrolysis derived char from municipal and industrial sludge: impact of organic decomposition and inorganic accumulation on the fuel characteristics of char. Waste Management 83, 131-141.
3.	Oh W.D., Lisak G., Liang Y.N., Veksha A., Moo J.G.S., Giannis A., Lim J.W., Lim T.T. (2018). Insights into the thermolytic transformation of lignocellulosic biomass waste to redox-active carbocatalyst: Durability of surface active sites. Applied Catalysis B: Environmental 233, 120-129.

*Biosolids (sewage sludge) from wastewater treatment plant*
1.	Chanaka Udayanga W.D., Veksha A., Giannis A., Lim T.T.* (2019). Pyrolysis derived char from municipal and industrial sludge: impact of organic decomposition and inorganic accumulation on the fuel characteristics of char. Waste Management 83, 131-141.
2.	Chanaka Udayanga W.D., Veksha A., Giannis A., Lisak G., Chang V.W.C., Lim T.T.* (2018). Fate and distribution of heavy metals during thermal processing of sewage sludge. Fuel 226, 721–744.
3.	Lim T.T.*, Chu J., Goi M.H. (2006). Effects of cement on redistribution of trace metals and dissolution of organics in sewage sludge and its inorganic waste-amended products. Waste Management 26(11), 1294-1304.
4.	Chu J., Goi M.H., Lim T.T.* (2005). Consolidation of cement treated sewage sludge using vertical drains. Canadian Geotechnical Journal 42(2), 528-540.
5.	Lim T.T.*, Chu J., Goi M.H. (2004). Assessment of heavy metals leachability in clay-amended sewage sludge stabilized with cement for use as fill material. Journal of Residuals Science & Technology 1(3), 157-164.

*MSW incinerator ashes*
1.	Lim T.T.*, Tay J.H., Tan L.C., Choa V., Teh C.I. (2004). Changes in mobility and speciation of heavy metals in clay-amended incinerator fly ash. Environmental Geology 47(1), 1-10.
2.	Lim T.T.*, Tay J.H., Wang J.Y. (2001). MSW fly ash treatment by acid and chelating agent for reuse. Proc., 17^th Int. Conf. On Solid Waste Technology and Management, Philadelphia, U.S.A., pp530-538.

Environmental remedial technologies

*Oil spill cleanup*
1.	Chaturabong P., Lim T.T.*, Wong Y.D. (2018). Effective surface treatment techniques for refinishing oil-stained road surface. Construction & Building Materials 159, 64-72.
2.	Chen B., Ma Q., Tan C., Lim T.T., Huang L., Zhang H. (2015). Carbon-based sorbents with three-dimensional architectures for water remediation. Small 11(27), 3319-3336.
3.	Lim T.T.* and Huang X.F. (2007). Evaluation of kapok (Ceiba pentandra (L.) Gaertn.) as a natural hollow hydrophobic-oleophilic fibrous sorbent for oil spill cleanup. Chemosphere 66(5), 955-963.
4.	Lim T.T.* and Huang X.F. (2007). Evaluation of hydrophobicity/oleophilicity of kapok and its performance in oily water filtration: comparison of raw and solvent-treated fibers. Industrial Crops and Products 26(2), 125–134.
5.	Huang X.F., Lim T.T.* (2006). The performance and mechanism of hydrophobic-oleophilic kapok filter for oil/water separation. Desalination 190, 295–307.
6.	*Lim T.T.,** Huang X.F. (2006). In-situ oil/water separation using hydrophobic-oleophilic fibrous wall: a lab-scale feasibility study for groundwater cleanup. Journal of Hazardous Materials B137, 820-826.

In the project of oil removal from water, my research group investigated oil removal from oily water, simulated aquifer, and oil spills on surface water using a kind of natural plant product which has hydrophobic-oleophilic property. The fibrous product has a hollow structure with large lumen. It is known as kapok by the native people living in the Southeast Asia. It is cheaper and has higher oil absorption capacity compared to cotton due to its lightweight and high specific volume.

Oil sorption by packed sorbent at various packing densities

*Contaminants removal from contaminated soils*
1.	Lim T.T.*, Chui P.C., Goh K.H. (2005). Process evaluation for optimization of EDTA use and recovery for heavy metal removal from a contaminated soil. Chemosphere 58(8), 1031-1040.
2.	Lim T.T.*, Tay J.H., Wang J.Y. (2004). Chelating-agent enhanced heavy metal extraction from a contaminated acidic soil. Journal of Environmental Engineering, ASCE, 130, 59-66.
3.	Goh K.H., Lim T.T.* (2005). Arsenic extractability in a fine soil fraction and influence of various anions on its mobility in subsurface environment. Applied Geochemistry 20(2), 229-239.
4.	Lim T.T.*, Goh K.H. (2005). Selenium extractability from a contaminated fine soil fraction: implication on soil cleanup. Chemosphere 58(1), 91-101.

International collaborations (past and present)

· Department of Civil Engineering, Monash University, Victoria, Australia

· School of Environmental Engineering (ENVENG), Technical University of Crete, Chania, Greece

· School of Chemical Sciences, Universiti Sains Malaysia, Penang, Malaysia

· School of Environment, Harbin Institute of Technology, Harbin, China

· School of Material Science and Engineering, Tsinghua University, Beijing, China

· Key Laboratory of Coal Science and Technology of Shanxi Province and Ministry of Education, Taiyuan University of Technology, Taiyuan, China

· College of Environment, Zhejiang University of Technology, Hangzhou, China

· School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan, China

· School of Environmental and Chemical Engineering, Shanghai University, Shanghai, China

· Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, China

· Key Lab of Groundwater Resources and Environment, Ministry of Education, Jilin University, Changchun, China

· Department of Chemical and Biological Engineering, University of Colorado, Boulder, Colorado, USA

· School of Chemical Engineering, University of New South Wales, Sydney, New South Wales, Australia

· School of Civil and Environmental Engineering, Pusan National University, Busan, Republic of Korea

· School of Civil Engineering, King Mongkut’s Institute of Technology Ladkrabang, Bangkok, Thailand

· Department of Civil & Environmental Engineering, Stanford University, Palo Alto, California, USA