Photocatalytic oxidation technology for humic acid removal using a nano-structured TiO2/Fe2O3 catalyst

Abstract

A novel TiO2 coated haematite photocatalyst was prepared and used for removal of colored humic acids from wastewater in an UV bubble photocatalytic reactor. XRD analysis confirmed that nano-size anatase crystals of TiO2 were formed after calcination at 480 degrees C. SEM results revealed that nano-size particles of TiO2 were uniformly coated on the surface of Fe2O3 to form a bulk of nano-structured photocatalyst Fe2O3/TiO2. The porous catalyst had a BET surface area of 168 m2/g. Both the color and total organic carbon (TOC) conversion versus the residence time were measured at various conditions. The effects of pH value, catalyst loaded, initial humic acid concentration and reaction temperature on conversion were monitored. The experimental results proved that the photocatalytic oxidation process was not temperature sensitive and the optimum catalyst loading was found to be 0.4 g/l. Degradation and decolorization of humic acids have higher efficiency in acidic medium and at low initial humic acid concentration. The new catalyst was effective in removing TOC at 61.58% and color400 at 93.25% at 180 minutes illumination time and for 20 mg/l neutral humic acid aqueous solution. The kinetic analysis showed thatthe rate of photocatalytic degradation of humic acids obeyed the first order reaction kinetics.

Photoelectrocatalytic degradation of tetracycline by highly effective TiO2 nanopore arrays electrode

“…TiO 2 -based photocatalytic (PC) and photoelectrocatalytic (PEC) oxidation technique have been proven to be promising and highly efficient processes that can be used to degrade various recalcitrant organic pollutants, such as dyes, pesticides, herbicides, aromatics, etc., under UV light irradiation [1][2][3][4][5][6][7]. Upon UV illumination, the electrons are excited from the valence band to the conduction band, generating the electron/hole pairs.…”

Humic acid and trihalomethane breakdown with potential by-product formations for atmospheric air plasma water treatment

“…Plasma treatment was performed at variable discharge voltage levels (60-80 kV) and treatment durations (0-30 min). After processing, the sealed reactors containing the sample were stored at room temperature of [16][17][18] C for 24 h to facilitate diffusion of the reactive species and reaction with the spiked compounds. No attempt was made to optimise the diffusion process, as the objective to this work was to study the effects of plasma treatment under controlled conditions.…”

“…Several approaches such as nanofiltration, ultrafiltration, reverse osmosis coagulation [13], activated carbon adsorption [14], Fenton treatment [15], nano-TiO 2 photocatalysis [16], membrane filtration [17], biological treatment [18], and ozonation [19] have been employed to remove humic substances and THM's. Biological processes, including the use of bio-filters may lead to the accumulation of suspended solids and release of bacteria [20].…”

Adsorption of humic acid by amine-modified nanocellulose: an experimental and simulation study

“…They explained that degradation and decolorization of HA were obtained with higher efficiency in acidic condition. First-order reaction kinetic was suitable for photocatalytic degradation (Qiao et al 2003 (Yang et al 2009). According to previous studies, different kinetic models were introduced to predict the mechanism of adsorption [including pseudofirst-order model, pseudo-second-order model, first-order reversible reaction model, Weber and Morris sorption kinetic model, external mass transfer model, Elovich's model, first-order equation of Bhattacharya and Venkobachar, and Ritchies's equation (Febrianto et al 2009)].…”