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Environmental problems - Chemical approaches
RESEARCH ARTICLE

Solar photocatalytic removal of arsenic from polluted water using carbon-modified titanium oxide nanoparticles supported on activated carbon

Radwan Kh. Alfarawati A , Yasser A. Shaban https://orcid.org/0000-0001-9236-4773 A B C , Adnan J. Turki A , Yasar N. Kavil A and Mousa I. Zobidi A
+ Author Affiliations
- Author Affiliations

A Marine Chemistry Department, Faculty of Marine Sciences, King Abdulaziz University, PO Box 80207, Jeddah 21589, Saudi Arabia.

B National Institute of Oceanography and Fisheries, Qayet Bay, Alexandria 21411, Egypt.

C Corresponding author. Email: yasrsh@yahoo.com

Environmental Chemistry 17(8) 568-578 https://doi.org/10.1071/EN19308
Submitted: 30 November 2019  Accepted: 9 April 2020   Published: 29 May 2020

Environmental context. Contamination of water resources with arsenic is a serious environmental problem requiring efficient, viable and environmentally safe As removal processes. This study reports an arsenic remediation strategy using carbon modified titanium dioxide supported on activated carbon as a photocatalyst. The study highlights a practical process for efficient remediation of As-contaminated water under natural sunlight.

Abstract. Carbon-modified titanium oxide nanoparticles supported on activated carbon (C-TiO2/AC) were synthesised by the sol-gel method. X-ray diffraction (XRD), scanning electron microscopy (SEM), UV-vis, energy dispersive X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS) were employed to characterise the crystal structure, surface morphology, and optical properties of the C-TiO2/AC nanoparticles. The performance of C-TiO2/AC was evaluated towards the photocatalytic oxidation of AsIII in simulated and real wastewater under illumination of both artificial UV and natural sunlight. Compared with activated carbon (AC), pure TiO2 and carbon-modified titanium oxide (C-TiO2), the combination of carbon modification of TiO2 and activated carbon (C-TiO2/AC) significantly enhanced the photocatalytic oxidation rate of AsIII. Complete removal of arsenic (2.66 ppm) from wastewater was attained by using C-TiO2/AC after 150 min under illumination of natural sunlight. However, the removal efficiency was declined remarkably to 58.4 and 37.3 % for C-TiO2 and pure TiO2 respectively. The highest removal rate of AsIII was achieved at the optimised conditions of 1.0 g L−1 of C-TiO2/AC and a solution pH of 9.

Additional keywords: C-TiO2/AC, photocatalysis.


References

Al-Azri ZHN, Chen WT, Chan A, Jovic V, Ina T, Idriss H, Waterhouse GIN (2015). The roles of metal co-catalysts and reaction media in photocatalytic hydrogen production: Performance evaluation of M/TiO2 photocatalysts (M = Pd, Pt, Au) in different alcohol–water mixtures. Journal of Catalysis 329, 355–367.
The roles of metal co-catalysts and reaction media in photocatalytic hydrogen production: Performance evaluation of M/TiO2 photocatalysts (M = Pd, Pt, Au) in different alcohol–water mixturesCrossref | GoogleScholarGoogle Scholar |

Amaniampong PN, Trinh QT, Varghese JJ, Behling R, Valange S, Mushrif SH, Jerome F (2018). Unraveling the mechanism of the oxidation of glycerol to dicarboxylic acids over a sonochemically synthesized copper oxide catalyst. Green Chemistry 20, 2730–2741.
Unraveling the mechanism of the oxidation of glycerol to dicarboxylic acids over a sonochemically synthesized copper oxide catalystCrossref | GoogleScholarGoogle Scholar |

Amaniampong PN, Trinh QT, Vigier KDO, Dao DQ, Tran NH, Wang Y, Sherburne MP, François Jérôme F (2019). Synergistic Effect of High-Frequency Ultrasound with Cupric Oxide Catalyst Resulting in a Selectivity Switch in Glucose Oxidation under Argon. Journal of the American Chemical Society 141, 14772–14779.
Synergistic Effect of High-Frequency Ultrasound with Cupric Oxide Catalyst Resulting in a Selectivity Switch in Glucose Oxidation under ArgonCrossref | GoogleScholarGoogle Scholar | 31450888PubMed |

Anpo M (1997). Photocatalysis on titanium oxide catalysts: Approaches in achieving highly efficient reactions and realizing the use of visible light. Catalysis Surveys from Asia 1, 169–179.
Photocatalysis on titanium oxide catalysts: Approaches in achieving highly efficient reactions and realizing the use of visible lightCrossref | GoogleScholarGoogle Scholar |

Asahi RY, Morikawa TA, Ohwaki T, Aoki K, Taga Y (2001). Visible-Light Photocatalysis in Nitrogen-Doped Titanium Oxides. Science 293, 269–271.
Visible-Light Photocatalysis in Nitrogen-Doped Titanium OxidesCrossref | GoogleScholarGoogle Scholar |

Asiltürk M, Şener Ş (2012). TiO2-activated carbon photocatalysts: Preparation, characterization and photocatalytic activities. Chemical Engineering Journal 180, 354–363.
TiO2-activated carbon photocatalysts: Preparation, characterization and photocatalytic activitiesCrossref | GoogleScholarGoogle Scholar |

Awual MR, Urata S, Jyo A, Tamada M, Katakai A (2008). Arsenate removal from water by a weak base anion exchange fibrous adsorbent. Water Research 42, 689–696.
Arsenate removal from water by a weak base anion exchange fibrous adsorbentCrossref | GoogleScholarGoogle Scholar | 17959217PubMed |

Babel S, Kurniawan TA (2003). Low-cost adsorbents for heavy metals uptake from contaminated water: a review. Journal of Hazardous Materials 97, 219–243.
Low-cost adsorbents for heavy metals uptake from contaminated water: a reviewCrossref | GoogleScholarGoogle Scholar | 12573840PubMed |

Basu A, Mahata J, Gupta S, Giri AK (2001). Genetic toxicology of a paradoxical human carcinogen, arsenic: a review. Mutation Research/Reviews in Mutation Research 488, 171–194.
Genetic toxicology of a paradoxical human carcinogen, arsenic: a reviewCrossref | GoogleScholarGoogle Scholar |

Baur GB, Beswick O, Spring J, Yuranov I, Kiwi-Minsker L (2015). Activated carbon fibers for efficient VOC removal from diluted streams: the role of surface functionalities. Adsorption 21, 255–264.
Activated carbon fibers for efficient VOC removal from diluted streams: the role of surface functionalitiesCrossref | GoogleScholarGoogle Scholar |

Bayarri B, Gimenez J, Curco D, Esplugas S (2005). Photocatalytic degradation of 2, 4-dichlorophenol by TiO2/UV: kinetics, actinometries and models. Catalysis Today 101, 227–236.
Photocatalytic degradation of 2, 4-dichlorophenol by TiO2/UV: kinetics, actinometries and modelsCrossref | GoogleScholarGoogle Scholar |

Chen WT, Chan A, Sun-Waterhouse D, Moriga T, Idriss H, Waterhouse GI (2015). Ni/TiO2: A promising low-cost photocatalytic system for solar H2 production from ethanol–water mixtures. Journal of Catalysis 326, 43–53.
Ni/TiO2: A promising low-cost photocatalytic system for solar H2 production from ethanol–water mixturesCrossref | GoogleScholarGoogle Scholar |

Choi W, Termin A, Hoffmann MR (1994). The Role of Metal Ion Dopants in Quantum-Sized TiO2: Correlation between Photoreactivity and Charge Carrier Recombination Dynamics. Journal of Physical Chemistry 98, 13669–13679.
The Role of Metal Ion Dopants in Quantum-Sized TiO2: Correlation between Photoreactivity and Charge Carrier Recombination DynamicsCrossref | GoogleScholarGoogle Scholar |

Choong TS, Chuah TG, Robiah Y, Koay FG, Azni I (2007). Arsenic toxicity, health hazards and removal techniques from water: an overview. Desalination 217, 139–166.
Arsenic toxicity, health hazards and removal techniques from water: an overviewCrossref | GoogleScholarGoogle Scholar |

Dao TH, Tran TT, Nguyen VR, Pham TNM, Vu CM, Pham TD (2018). Removal of antibiotic from aqueous solution using synthesized TiO2 nanoparticles: characteristics and mechanisms. Environmental Earth Sciences 77, 359
Removal of antibiotic from aqueous solution using synthesized TiO2 nanoparticles: characteristics and mechanismsCrossref | GoogleScholarGoogle Scholar |

DeMarco MJ, Sen Gupta AK, Greenleaf JE (2003). Arsenic removal using polymeric/inorganic hybrid sorbent. Water Research 37, 164–176.
Arsenic removal using polymeric/inorganic hybrid sorbentCrossref | GoogleScholarGoogle Scholar | 12465798PubMed |

Demeestere K, Dewulf J, Ohno T, Salgado PH, Van Langenhove H (2005). Visible light mediated photocatalytic degradation of gaseous trichloroethylene and dimethyl sulfide on modified titanium dioxide. Applied Catalysis B: Environmental 61, 140–149.
Visible light mediated photocatalytic degradation of gaseous trichloroethylene and dimethyl sulfide on modified titanium dioxideCrossref | GoogleScholarGoogle Scholar |

Do HH, Nguyen DLT, Nguyen XC, Le T-H, Nguyen TP, Trinh QT, Ahn SH, Vo D-VN, Kim SY, Le QV (2020). Recent progress in TiO2-based photocatalysts for hydrogen evolution reaction: A review. Arabian Journal of Chemistry 13, 3653–3671.
Recent progress in TiO2-based photocatalysts for hydrogen evolution reaction: A reviewCrossref | GoogleScholarGoogle Scholar |

Dolat D, Quici N, Kusiak-Nejman E, Morawski AW, Puma GL (2012). One-step, hydrothermal synthesis of nitrogen, carbon co-doped titanium dioxide (N, CTiO2) photocatalysts. Effect of alcohol degree and chain length as carbon dopant precursors on photocatalytic activity and catalyst deactivation. Applied Catalysis B: Environmental 115–116, 81–89.
One-step, hydrothermal synthesis of nitrogen, carbon co-doped titanium dioxide (N, CTiO2) photocatalysts. Effect of alcohol degree and chain length as carbon dopant precursors on photocatalytic activity and catalyst deactivationCrossref | GoogleScholarGoogle Scholar |

Driehaus W, Seith R, Jekel M (1995). Oxidation of arsenic (III) with manganese oxides in water treatment. Water Research 29, 297–305.
Oxidation of arsenic (III) with manganese oxides in water treatmentCrossref | GoogleScholarGoogle Scholar |

Driehaus W, Jekel M, Hildebrandt U (1998). Granular ferric hydroxide—a new adsorbent for the removal of arsenic from natural water. Journal of Water Supply: Research & Technology – Aqua 47, 30–35.
Granular ferric hydroxide—a new adsorbent for the removal of arsenic from natural waterCrossref | GoogleScholarGoogle Scholar |

Dutta PK, Pehkonen SO, Sharma VK, Ray AK (2005). Photocatalytic oxidation of arsenic(III): evidence of hydroxyl radicals. Environmental Science & Technology 39, 1827–1834.
Photocatalytic oxidation of arsenic(III): evidence of hydroxyl radicalsCrossref | GoogleScholarGoogle Scholar |

El-Sheikh SM, Zhang G, El-Hosainy HM, Ismail AA, O’Shea KE, Falaras P, Kontos AG, Dionysiou DD (2014). High performance sulfur, nitrogen and carbon doped mesoporous anatase–brookite TiO2 photocatalyst for the removal of microcystin-LR under visible light irradiation. Journal of Hazardous Materials 280, 723–733.
High performance sulfur, nitrogen and carbon doped mesoporous anatase–brookite TiO2 photocatalyst for the removal of microcystin-LR under visible light irradiationCrossref | GoogleScholarGoogle Scholar | 25238189PubMed |

Environmental Protection Agency (EPA) (2001). National primary drinking water regulations: arsenic and clarifications to compliance and new source contaminants monitoring. Federal Register 66, 6976–7066.

Etacheri V, Michlits G, Seery MK, Hinder SJ, Pillai SC (2013). A highly efficient TiO2-XCx nano-heterojunction photocatalyst for visible-light induced antibacterial applications. ACS Applied Materials & Interfaces 5, 1663–1672.
A highly efficient TiO2-XCx nano-heterojunction photocatalyst for visible-light induced antibacterial applicationsCrossref | GoogleScholarGoogle Scholar |

Guan X, Ma J, Dong H, Jiang L (2009). Removal of arsenic from water: effect of calcium ions on As(III) removal in the KMnO4 Fe(II) process. Water Research 43, 5119–5128.
Removal of arsenic from water: effect of calcium ions on As(III) removal in the KMnO4 Fe(II) processCrossref | GoogleScholarGoogle Scholar | 19201439PubMed |

Guo X, Mao D, Lu G, Wang S, Wu G (2011). The influence of La doping on the catalytic behavior of Cu/ZrO2 for methanol synthesis from CO2 hydrogenation. Journal of Molecular Catalysis A: Chemical 345, 60–68.
The influence of La doping on the catalytic behavior of Cu/ZrO2 for methanol synthesis from CO2 hydrogenationCrossref | GoogleScholarGoogle Scholar |

Hansen HK, Ribeiro A, Mateus E (2006). Biosorption of arsenic(V) with Lessonia nigrescens. Minerals Engineering 19, 486–490.
Biosorption of arsenic(V) with Lessonia nigrescensCrossref | GoogleScholarGoogle Scholar |

Hoffmann MR, Martin ST, Choi W, Bahnemann DW (1995). Environmental Applications of Semiconductor Photocatalysis. Chemical Reviews 95, 69–96.
Environmental Applications of Semiconductor PhotocatalysisCrossref | GoogleScholarGoogle Scholar |

Hug SJ, Leupin O (2003). Iron-catalyzed oxidation of arsenic (III) by oxygen and by hydrogen peroxide: pH-dependent formation of oxidants in the Fenton reaction. Environmental Science & Technology 37, 2734–2742.
Iron-catalyzed oxidation of arsenic (III) by oxygen and by hydrogen peroxide: pH-dependent formation of oxidants in the Fenton reactionCrossref | GoogleScholarGoogle Scholar |

Iberhan L, Wisniewski M (2003). Removal of arsenic(III) and arsenic(V) from sulfuric acid solution by liquid–liquid extraction. Journal of Chemical Technology and Biotechnology 78, 659–665.
Removal of arsenic(III) and arsenic(V) from sulfuric acid solution by liquid–liquid extractionCrossref | GoogleScholarGoogle Scholar |

Ibusuki T, Takeuchi KJ (1994). Removal of low concentration nitrogen oxides through photoassisted heterogeneous catalysis. Journal of Molecular Catalysis 88, 93–102.
Removal of low concentration nitrogen oxides through photoassisted heterogeneous catalysisCrossref | GoogleScholarGoogle Scholar |

Ishitani O, Inoue C, Suzuki Y, Ibusuki T (1993). Photocatalytic reduction of carbon dioxide to methane and acetic acid by an aqueous suspension of metal-deposited TiO2. Journal of Photochemistry and Photobiology A: Chemistry 72, 269–271.
Photocatalytic reduction of carbon dioxide to methane and acetic acid by an aqueous suspension of metal-deposited TiO2Crossref | GoogleScholarGoogle Scholar |

Jang M, Min SH, Kim TH, Park JK (2006). Removal of Arsenite and Arsenate Using Hydrous Ferric Oxide Incorporated into Naturally Occurring Porous Diatomite. Environmental Science & Technology 40, 1636–1643.
Removal of Arsenite and Arsenate Using Hydrous Ferric Oxide Incorporated into Naturally Occurring Porous DiatomiteCrossref | GoogleScholarGoogle Scholar |

Janus M, Inagaki M, Tryba B, Toyoda M, Moraswski AW (2006). Carbon modified TiO2 photocatalyst by ethanol carbonization. Applied Catalysis B: Environmental 63, 272–276.
Carbon modified TiO2 photocatalyst by ethanol carbonizationCrossref | GoogleScholarGoogle Scholar |

Karimi L, Zohoori S, Yazdanshenas ME (2014). Photocatalytic degradation of azo dyes in aqueous solutions under UV irradiation using nano-strontium titanate as the nanophotocatalyst. Journal of Saudi Chemical Society 18, 581–588.
Photocatalytic degradation of azo dyes in aqueous solutions under UV irradiation using nano-strontium titanate as the nanophotocatalystCrossref | GoogleScholarGoogle Scholar |

Kavil YN, Shaban YA, Al Farawati RK, Orif MI, Zobidi M, Khan SU (2017). Photocatalytic conversion of CO2 into methanol over Cu-C/TiO2 nanoparticles under UV light and natural sunlight. Journal of Photochemistry and Photobiology A: Chemistry 347, 244–253.
Photocatalytic conversion of CO2 into methanol over Cu-C/TiO2 nanoparticles under UV light and natural sunlightCrossref | GoogleScholarGoogle Scholar |

Kavitha R, Devi LG (2014). Synergistic effect between carbon dopant in titania lattice and surface carbonaceous species for enhancing the visible light photocatalysis. Journal of Environmental Chemical Engineering 2, 857–867.
Synergistic effect between carbon dopant in titania lattice and surface carbonaceous species for enhancing the visible light photocatalysisCrossref | GoogleScholarGoogle Scholar |

Khan SU, Al-Shahry M, Ingler WB (2002). Efficient Photochemical Water Splitting by a Chemically Modified n-TiO2. Science 297, 2243–2245.
Efficient Photochemical Water Splitting by a Chemically Modified n-TiO2Crossref | GoogleScholarGoogle Scholar | 12351783PubMed |

Kim J, Benjamin MM (2004). Modeling a novel ion exchange process for arsenic and nitrate removal. Water Research 38, 2053–2062.
Modeling a novel ion exchange process for arsenic and nitrate removalCrossref | GoogleScholarGoogle Scholar | 15087186PubMed |

Kim MJ, Nriangu J (2000). Oxidation of arsenite in groundwater using ozone and oxygen. The Science of the Total Environment 247, 71–79.
Oxidation of arsenite in groundwater using ozone and oxygenCrossref | GoogleScholarGoogle Scholar | 10721144PubMed |

Kim HD, Kim WK, Cho J (2006). Removal and transport mechanisms of arsenics in UF and NF membrane processes. Journal of Water and Health 4, 215–223.
Removal and transport mechanisms of arsenics in UF and NF membrane processesCrossref | GoogleScholarGoogle Scholar |

Kordmostafapour F, Pourmoghadas H, Shahmansouri MR, Parvaresh A (2006). Arsenic removal by dissolved air flotation. Journal of Applied Sciences 6, 1153–1158.
Arsenic removal by dissolved air flotationCrossref | GoogleScholarGoogle Scholar |

Kubelka P (1948). New Contributions to the optics of intensely light scattering materials. Part I. Journal of the Optical Society of America 38, 448–457.
New Contributions to the optics of intensely light scattering materials. Part ICrossref | GoogleScholarGoogle Scholar | 18916891PubMed |

Kumar PR, Chaudhari S, Khilar KC, Mahajan SP (2004). Removal of arsenic from water by electrocoagulation. Chemosphere 55, 1245–1252.
Removal of arsenic from water by electrocoagulationCrossref | GoogleScholarGoogle Scholar |

Kusvuran E, Samil A, Atanur OM, Erbatur O (2005). Photocatalytic degradation kinetics of di- and tri-substituted phenolic compound in aqueous solution by TiO2/UV. Applied Catalysis B: Environmental 58, 211–216.
Photocatalytic degradation kinetics of di- and tri-substituted phenolic compound in aqueous solution by TiO2/UVCrossref | GoogleScholarGoogle Scholar |

Lee H, Choi W (2002). Photocatalytic oxidation of arsenite in TiO2 suspension: kinetics and mechanisms. Environmental Science & Technology 36, 3872–3878.
Photocatalytic oxidation of arsenite in TiO2 suspension: kinetics and mechanismsCrossref | GoogleScholarGoogle Scholar |

Lei XF, Xue XX, Yang H, Chen C, Li X, Niu MC, Gao XY, Yang YT (2015). Effect of calcination temperature on the structure and visible-light photocatalytic activities of (N, S and C) co-doped TiO2 nano-materials. Applied Surface Science 332, 172–180.
Effect of calcination temperature on the structure and visible-light photocatalytic activities of (N, S and C) co-doped TiO2 nano-materialsCrossref | GoogleScholarGoogle Scholar |

Lettmann C, Hildenbrand K, Kisch H, Macyk W, Maier WF (2001). Visible light photodegradation of 4-chlorophenol with a coke-containing titanium dioxide photocatalyst. Applied Catalysis B: Environmental 32, 215–227.
Visible light photodegradation of 4-chlorophenol with a coke-containing titanium dioxide photocatalystCrossref | GoogleScholarGoogle Scholar |

Leupin OX, Hug SJ (2005). Oxidation and removal of arsenic(III) from aerated groundwater by filtration through sand and zero-valent iron. Water Research 39, 1729–1740.
Oxidation and removal of arsenic(III) from aerated groundwater by filtration through sand and zero-valent ironCrossref | GoogleScholarGoogle Scholar | 15899271PubMed |

Li B, Hakuta Y, Hayashi H (2005a). Hydrothermal synthesis of crystalline rectangular titanoniobate particles. Chemical Communications 1732–1734.
Hydrothermal synthesis of crystalline rectangular titanoniobate particlesCrossref | GoogleScholarGoogle Scholar | 15791314PubMed |

Li Y, Hwang DS, Lee NH, Kim SJ (2005b). Synthesis and characterization of carbon-doped titania as an artificial solar light sensitive photocatalyst. Chemical Physics Letters 404, 25–29.
Synthesis and characterization of carbon-doped titania as an artificial solar light sensitive photocatalystCrossref | GoogleScholarGoogle Scholar |

Li H, Li J, Huo Y (2006). Highly active TiO2N photocatalysts prepared by treating TiO2 precursors in NH3/ethanol fluid under supercritical conditions. The Journal of Physical Chemistry B 110, 1559–1565.
Highly active TiO2N photocatalysts prepared by treating TiO2 precursors in NH3/ethanol fluid under supercritical conditionsCrossref | GoogleScholarGoogle Scholar | 16471715PubMed |

Li F, Sun S, Jiang Y, Xia M, Sun M, Xue B (2008). Photodegradation of an azo dye using immobilized nanoparticles of TiO2 supported by natural porous mineral. Journal of Hazardous Materials 152, 1037–1044.
Photodegradation of an azo dye using immobilized nanoparticles of TiO2 supported by natural porous mineralCrossref | GoogleScholarGoogle Scholar | 17869418PubMed |

Lin J, Yu JC (1998). An investigation on photocatalytic activities of mixed TiO2-rare earth oxides for the oxidation of acetone in air. Journal of Photochemistry and Photobiology A: Chemistry 116, 63–67.
An investigation on photocatalytic activities of mixed TiO2-rare earth oxides for the oxidation of acetone in airCrossref | GoogleScholarGoogle Scholar |

Liu S, Yu J, Jaroniec M (2010). Tunable photocatalytic selectivity of hollow TiO2 microspheres composed of anatase polyhedra with exposed {001} facets. Journal of the American Chemical Society 132, 11914–11916.
Tunable photocatalytic selectivity of hollow TiO2 microspheres composed of anatase polyhedra with exposed {001} facetsCrossref | GoogleScholarGoogle Scholar | 20687566PubMed |

Liu J, Han L, Ma H, Tian H, Yang J, Zhang Q, Seligmann BJ, Wang S, Liu J (2016). Template-free synthesis of carbon doped TiO2 mesoporous microplates for enhanced visible light photodegradation. Science Bulletin 61, 1543–1550.
Template-free synthesis of carbon doped TiO2 mesoporous microplates for enhanced visible light photodegradationCrossref | GoogleScholarGoogle Scholar |

Mai FD, Lu CS, Wu CW, Huang CH, Chen JY, Chen CC (2008). Mechanisms of photocatalytic degradation of Victoria Blue R using nano-TiO2. Separation and Purification Technology 62, 423–436.
Mechanisms of photocatalytic degradation of Victoria Blue R using nano-TiO2Crossref | GoogleScholarGoogle Scholar |

Maira AJ, Yeung KL, Lee CY, Yue PL, Chan CK (2000). Size effects in gas-phase photo-oxidation of trichloroethylene using nanometer-sized TiO2 catalysts. Journal of Catalysis 192, 185–196.
Size effects in gas-phase photo-oxidation of trichloroethylene using nanometer-sized TiO2 catalystsCrossref | GoogleScholarGoogle Scholar |

Maiti A, DasGupta S, Basu JK, De S (2007). Adsorption of arsenite using natural laterite as adsorbent. Separation and Purification Technology 55, 350–359.
Adsorption of arsenite using natural laterite as adsorbentCrossref | GoogleScholarGoogle Scholar |

Manoharan RK, Sankaran S (2018). Photocatalytic degradation of organic pollutant aldicarb by non-metal-doped nanotitania: synthesis and characterization. Environmental Science and Pollution Research 25, 20510–20517.
Photocatalytic degradation of organic pollutant aldicarb by non-metal-doped nanotitania: synthesis and characterizationCrossref | GoogleScholarGoogle Scholar |

Nakano Y, Morikawa T, Ohwaki T, Taga Y (2005). Electrical characterization of band gap states in C-doped TiO2 films. Applied Physics Letters 87, 052111
Electrical characterization of band gap states in C-doped TiO2 filmsCrossref | GoogleScholarGoogle Scholar |

Negishi N, Iyoda T, Hashimoto K, Fujishima A (1995). Preparation of Transparent TiO2 Thin Film Photocatalyst and Its Photocatalytic Activity. Chemistry Letters 24, 841–842.
Preparation of Transparent TiO2 Thin Film Photocatalyst and Its Photocatalytic ActivityCrossref | GoogleScholarGoogle Scholar |

Neppolian B, Choi HC, Sakthivel S, Arabindoo B, Murugesan V (2002). Solar/UV-induced photocatalytic degradation of three commercial textile dyes. Journal of Hazardous Materials 89, 303–317.
Solar/UV-induced photocatalytic degradation of three commercial textile dyesCrossref | GoogleScholarGoogle Scholar | 11744213PubMed |

Neppolian B, Kanel SR, Choi HC, Shankar MV, Arabindoo B, Murugesan V (2003). Photocatalytic degradation of reactive yellow 17 dye in aqueous solution in the presence of TiO2 with cement binder. International Journal of Photoenergy 5, 45–49.
Photocatalytic degradation of reactive yellow 17 dye in aqueous solution in the presence of TiO2 with cement binderCrossref | GoogleScholarGoogle Scholar |

Nikolaidis NP, Dobbs GM, Lackovic JA (2003). Arsenic removal by zero-valent iron: field, laboratory and modeling studies. Water Research 37, 1417–1425.
Arsenic removal by zero-valent iron: field, laboratory and modeling studiesCrossref | GoogleScholarGoogle Scholar | 12598205PubMed |

Oppenlander T (2003). ‘Photochemical purification of water and air.’ (Wiley-VCH: Weinheim)

Park H, Choi W (2005). Photocatalytic Reactivities of Nafion-Coated TiO2 for the Degradation of Charged Organic Compounds under UV or Visible Light. The Journal of Physical Chemistry B 109, 11667–11674.
Photocatalytic Reactivities of Nafion-Coated TiO2 for the Degradation of Charged Organic Compounds under UV or Visible LightCrossref | GoogleScholarGoogle Scholar | 16852432PubMed |

Parsons S (2004). ‘Advanced oxidation processes for water and wastewater treatment.’ (IWA Publishing: Cornwall)

Pena ME, Korfiatis GP, Patel M, Lippincott L, Meng X (2005). Adsorption of As (V) and As (III) by nanocrystalline titanium dioxide. Water Research 39, 2327–2337.
Adsorption of As (V) and As (III) by nanocrystalline titanium dioxideCrossref | GoogleScholarGoogle Scholar | 15896821PubMed |

Petukhov AV (1997). Effect of molecular mobility on kinetics of an electrochemical Langmuir-Hinshelwood reaction. Chemical Physics Letters 277, 539–544.
Effect of molecular mobility on kinetics of an electrochemical Langmuir-Hinshelwood reactionCrossref | GoogleScholarGoogle Scholar |

Pouretedal HR, Norozi A, Keshavarz MH, Semnani A (2009). Nanoparticles of zinc sulfide doped with manganese, nickel and copper as nanophotocatalyst in the degradation of organic dyes. Journal of Hazardous Materials 162, 674–681.
Nanoparticles of zinc sulfide doped with manganese, nickel and copper as nanophotocatalyst in the degradation of organic dyesCrossref | GoogleScholarGoogle Scholar | 18603365PubMed |

Rajesh KM, Sugunan S (2012). Effect of mechanical stirring on the preparation of high visible light active NS co-doped nano titania: synthesis and characterisation. IOSR Journal of Applied Chemistry 2, 36–42.
Effect of mechanical stirring on the preparation of high visible light active NS co-doped nano titania: synthesis and characterisationCrossref | GoogleScholarGoogle Scholar |

Reddy KM, Baruwati B, Jayalakshmi M, Rao MM (2005). S-, N-and C-doped titanium dioxide nanoparticles: synthesis, characterization and redox charge transfer study. Journal of Solid State Chemistry 178, 3352–3358.
S-, N-and C-doped titanium dioxide nanoparticles: synthesis, characterization and redox charge transfer studyCrossref | GoogleScholarGoogle Scholar |

Sakatani Y, Ando H, Okusako K, Koike H, Nunoshige J, Takata T, Kondo JN, Hara M, Domen K (2004). Metal ion and N co-doped TiO2 as a visible-light photocatalyst. Journal of Materials Research 19, 2100–2108.
Metal ion and N co-doped TiO2 as a visible-light photocatalystCrossref | GoogleScholarGoogle Scholar |

Sakthivel S, Kisch H (2003). Daylight photocatalysis by carbon-modified titanium dioxide. Angewandte Chemie International Edition 42, 4908–4911.
Daylight photocatalysis by carbon-modified titanium dioxideCrossref | GoogleScholarGoogle Scholar | 14579435PubMed |

Senthilvelan S, Chandraboss VL, Karthikeyan B, Natanapatham L, Murugavelu M (2013). TiO2, ZnO and nanobimetallic silica catalyzed photodegradation of methyl green. Materials Science in Semiconductor Processing 16, 185–192.
TiO2, ZnO and nanobimetallic silica catalyzed photodegradation of methyl greenCrossref | GoogleScholarGoogle Scholar |

Seshadri H, Chitra S, Paramasivan K, Sinha PK (2008). Photocatalytic degradation of liquid waste containing EDTA. Desalination 232, 139–144.
Photocatalytic degradation of liquid waste containing EDTACrossref | GoogleScholarGoogle Scholar |

Shaban YA (2019). Solar light-induced photodegradation of chrysene in seawater in the presence of carbon-modified n-TiO2 nanoparticles. Arabian Journal of Chemistry 12, 652–663.
Solar light-induced photodegradation of chrysene in seawater in the presence of carbon-modified n-TiO2 nanoparticlesCrossref | GoogleScholarGoogle Scholar |

Shaban YA, El Sayed MA, El Maradny AA, Al Farawati RK, Al Zobidi MI (2013). Photocatalytic degradation of phenol in natural seawater using visible light active carbon modified (CM)-n-TiO2 nanoparticles under UV light and natural sunlight illuminations. Chemosphere 91, 307–313.
Photocatalytic degradation of phenol in natural seawater using visible light active carbon modified (CM)-n-TiO2 nanoparticles under UV light and natural sunlight illuminationsCrossref | GoogleScholarGoogle Scholar | 23261126PubMed |

Sharma VK, Sohn M (2009). Aquatic arsenic: toxicity, speciation, transformations, and remediation. Environment International 35, 743–759.
Aquatic arsenic: toxicity, speciation, transformations, and remediationCrossref | GoogleScholarGoogle Scholar | 19232730PubMed |

Singh TS, Pant KK (2004). Equilibrium, kinetics and thermodynamic studies for adsorption of As(III) on activated alumina. Separation and Purification Technology 36, 139–147.
Equilibrium, kinetics and thermodynamic studies for adsorption of As(III) on activated aluminaCrossref | GoogleScholarGoogle Scholar |

Smedley PL, Kinniburgh DG (2002). A review of the source, behaviour and distribution of arsenic in natural waters. Applied Geochemistry 17, 517–568.
A review of the source, behaviour and distribution of arsenic in natural watersCrossref | GoogleScholarGoogle Scholar |

Sohrabnezhad S, Pourahmad A, Radaee E (2009). Photocatalytic degradation of basic blue 9 by CoS nanoparticles supported on AlMCM-41 material as a catalyst. Journal of Hazardous Materials 170, 184–190.
Photocatalytic degradation of basic blue 9 by CoS nanoparticles supported on AlMCM-41 material as a catalystCrossref | GoogleScholarGoogle Scholar | 19473761PubMed |

Tao YG, Xu YQ, Pan J, Gu H, Qin CY, Zhou P (2012). Glycine assisted synthesis of flower-like TiO2 hierarchical spheres and its application in photocatalysis. Materials Science and Engineering 177, 1664–1671.
Glycine assisted synthesis of flower-like TiO2 hierarchical spheres and its application in photocatalysisCrossref | GoogleScholarGoogle Scholar |

Tauc J, Grigorovici R, Vancu A (1966). Optical properties and electronic structure of amorphous germanium. Physica Status Solidi B 15, 627–637.
Optical properties and electronic structure of amorphous germaniumCrossref | GoogleScholarGoogle Scholar |

Trevisan V, Olivo A, Pinna F, Signoretto M, Vindigni F, Cerrato G, Bianchi CL (2014). CN/TiO2 photocatalysts: effect of co-doping on the catalytic performance under visible light. Applied Catalysis B: Environmental 160–161, 152–160.
CN/TiO2 photocatalysts: effect of co-doping on the catalytic performance under visible lightCrossref | GoogleScholarGoogle Scholar |

Trinh QT, Yang J, Lee JY, Saeys M (2012). Computational and experimental study of the Volcano behavior of the oxygen reduction activity of PdM@PdPt/C (M = Pt, Ni, Co, Fe, and Cr) core-shell electrocatalysts. Journal of Catalysis 291, 26–35.
Computational and experimental study of the Volcano behavior of the oxygen reduction activity of PdM@PdPt/C (M = Pt, Ni, Co, Fe, and Cr) core-shell electrocatalystsCrossref | GoogleScholarGoogle Scholar |

Trinh QT, Bhola K, Amaniampong PN, Jerome F, Mushrif SH (2018). Synergistic Application of XPS and DFT to Investigate Metal Oxide Surface Catalysis. The Journal of Physical Chemistry C 122, 22397–22406.
Synergistic Application of XPS and DFT to Investigate Metal Oxide Surface CatalysisCrossref | GoogleScholarGoogle Scholar |

Umebayashi T, Yamaki T, Itoh H, Asai K (2002). Band gap narrowing of titanium dioxide by sulfur doping. Applied Physics Letters 81, 454–456.
Band gap narrowing of titanium dioxide by sulfur dopingCrossref | GoogleScholarGoogle Scholar |

Wagemaker M, Borghols WJ, Mulder FM (2007). Large impact of particle size on insertion reactions. A case for anatase LixTiO2. Journal of the American Chemical Society 129, 4323–4327.
Large impact of particle size on insertion reactions. A case for anatase LixTiO2Crossref | GoogleScholarGoogle Scholar | 17362005PubMed |

Waypa JJ, Elimelech M, Hering JG (1997). Arsenic removal by RO and NF membranes. Journal of the American Water Works Association 89, 102–114.
Arsenic removal by RO and NF membranesCrossref | GoogleScholarGoogle Scholar |

Xiao P, Wang P, Li H, Li Q, Shi Y, Wu XL, Lin H, Chen J, Wang X (2018). New insights into bisphenols removal by nitrogen-rich nanocarbons: synergistic effect between adsorption and oxidative degradation. Journal of Hazardous Materials 345, 123–130.
New insights into bisphenols removal by nitrogen-rich nanocarbons: synergistic effect between adsorption and oxidative degradationCrossref | GoogleScholarGoogle Scholar | 29153971PubMed |

Xu C, Killmeyer R, Gray ML, Khan SU (2006). Photocatalytic effect of carbon-modified n-TiO2 nanoparticles under visible light illumination. Applied Catalysis B: Environmental 64, 312–317.
Photocatalytic effect of carbon-modified n-TiO2 nanoparticles under visible light illuminationCrossref | GoogleScholarGoogle Scholar |

Xue G, Liu HH, Chen QY, Hills C, Tyrer M, Innocent F (2011). Synergy between surface adsorption and photocatalysis during degradation of humic acid on TiO2/activated carbon composites. Journal of Hazardous Materials 186, 765–772.
Synergy between surface adsorption and photocatalysis during degradation of humic acid on TiO2/activated carbon compositesCrossref | GoogleScholarGoogle Scholar | 21163573PubMed |

Yamaguti K, Sato S (1985). Photolysis of water over metallized powdered titanium dioxide. Journal of the Chemical Society, Faraday Transactions 1 81, 1237–1246.
Photolysis of water over metallized powdered titanium dioxideCrossref | GoogleScholarGoogle Scholar |

Zhang X, Wu F, Wu X, Chen P, Deng N (2008). Photodegradation of acetaminophen in TiO2 suspended solution. Journal of Hazardous Materials 157, 300–307.
Photodegradation of acetaminophen in TiO2 suspended solutionCrossref | GoogleScholarGoogle Scholar | 18276070PubMed |

Zhang G, Zhang YC, Nadagouda M, Han C, O’Shea K, El-Sheikh SM, Ismail AA, Dionysiou DD (2014). Visible lightsensitized S, N and C co-doped polymorphic TiO2 for photocatalytic destruction of microcystin-LR. Applied Catalysis B: Environmental 144, 614–621.
Visible lightsensitized S, N and C co-doped polymorphic TiO2 for photocatalytic destruction of microcystin-LRCrossref | GoogleScholarGoogle Scholar |