Degradation of paraquat from contaminated water using green TiO2 nanoparticles synthesized from Coffea arabica L. in photocatalytic process

• Published in: Water science and technology 2019-03, Vol.79 (5), p.905-910
• Main Authors: Phuinthiang, Patcharaporn, Kajitvichyanukul, Puangrat
• Format: Article
• Language: English
• Subjects: Acids; Aqueous solutions; Caffeine; Catalysis; Catalysts; Chemicals; Coffea arabica; Coffee; Constants; Degradation; Efficiency; Experiments; Gels; Green chemistry; Herbicides; Hydrogen peroxide; Nanomaterials; Nanoparticles; Organic chemistry; Oxidation; Paraquat; Phenols; Photocatalysis; Photochemistry; Polyphenols; Rate constants; Sol-gel processes; Synthesis; Titanium; Titanium dioxide; Ultraviolet radiation; Water pollution
• ISSN: 0273-1223; 1996-9732
• DOI: 10.2166/wst.2018.493

The TiO2 nanoparticles synthesized from the extract of Coffea arabica L. (or TiO2/C) were used to remove paraquat from contaminated water in heterogeneous photocatalysis process. In this work, the sol-gel process using Coffea arabica L. as the solvent chemical were performed to obtain the TiO2 nano-catalyst. The value of pHpzc of TiO2/C was 2.9 which caused a highly acidic surface of catalyst. The paraquat is effectively removed in alkaline medium due to the adsorption ability of paraquat on the surface of TiO2/C. The paraquat degradation followed the pseudo-first-order model with the apparent rate constants of 5.84 × 10−2, 4.08 × 10−2, and 2.28 × 10−2 min−1 for TiO2/C, TiO2, and without TiO2, respectively, under the presence of ultraviolet (UV) and H2O2. The combined TiO2/C with UV and H2O2 was the most efficient process, exhibiting a maximum 66.3% degradation of 50 mg/L over 90 min at pH 10.