Removal of chemical oxygen demand from agro effluent by ZnO photocatalysis and photo-Fenton

Abstract

The direct discharge of improperly treated effluent from sago industry poses a great threat to water bodies due to the high amount of organic matter. This work investigated ZnO photocatalytic degradation under aerated and non-aerated conditions, and photo-Fenton aiming to reduce the chemical oxygen demand in sago effluent. Photolysis of sago effluent in the presence of ultraviolet irradiation and aeration resulted in 68% of the chemical oxygen demand removal. The results indicate high chemical oxygen demand reductions for different concentrations of sago effluent at 1:10, 1:100, and 1:1000 diluted with distilled water following the ZnO photocatalytic treatment under the aerated conditions. The chemical oxygen demand reductions of 90-95% and 85% were obtained using 3 g/L of ZnO, after 2 h of aerated and nonaerated photocatalytic treatments, respectively, for the sago effluent ratio of 1:1000. On the other hand, the combination of the most concentrated sago effluent at 1:10 and non-aerated ZnO photocatalytic treatment resulted in no appreciable chemical oxygen demand reduction at only 8%. The concentrations of Fe 2+ (10-60 mM) and H 2 O 2 (50-150 mM) greatly influenced the degradation rates of chemical oxygen demand. The optimum parameters of 10 mM of Fe 2+ and 50 mM of H 2 O 2 were able to reduce 97% of the chemical oxygen demand of the 1:1000 sago effluent under the photo-Fenton treatment with 2 h of ultraviolet irradiation. Thus, both ZnO photocatalysis and photo-Fenton can be applied as the possible treatment methods to reduce the chemical oxygen demand in effluent from sago processing.

Multifunctional 3D Hierarchical Bioactive Green Carbon-Based Nanocomposites

“…It is vividly shown that each of the nanoparticles has a rather low activity in the photodegradation of MB; however, a critical synergistic effect of those nanoparticles on each other enhanced the photocatalytic activity of the as-prepared nanocomposite and made it a promising choice for further studies. Additionally, the chemical oxygen demand (COD) method , was applied to investigate the quantitative degradation of MB as a pollutant. Based on the results (Figure S10), for the individual nanoparticles, Fe 3 O 4 and ZnO, the COD percentages are low, and in combination with the carbon-based nanomaterials, rGO and MWCNT, the COD percentages increased up to an unprecedented level over 90% for the rGO/MWCNT/Fe 3 O 4 /ZnO nanocomposite.…”

Heterogeneous Ternary Metal Oxide Nanocomposites for Improved Advanced Oxidation Process under Visible Light

“…In this way, a chain reaction of free radicals was obtained in a cascaded form and these free radicals are bombarding on dye molecules and destruct them, and thereby, organic‐contaminants‐free water was obtained. [ 55 ]…”

“…In this way, a chain reaction of free radicals was obtained in a cascaded form and these free radicals are bombarding on dye molecules and destruct them, and thereby, organic-contaminants-free water was obtained. [55] 3.6. COD and BOD COD and BOD tests were analyzed for heterogeneous CTZ0-CTZ4 nanocomposites before and after the AOP, as shown in Tables 2 and 3.…”

Nonlinear Fitting for Estimation of Adsorption Equilibrium, Kinetic and Thermodynamic Parameters of Methylene Blue onto Activated Carbon

“…Pollution of the aquatic environment resulting from the discharging of insufficiently treated industrial wastes containing relatively large quantities of some chemicals of industrial origin, such as dyes, phenols, coloring materials, pesticides, and fertilizers, into water sources is a growing environmental problem and a direct threat to the life of all living organisms (1). In addition to being a major factor causing a lack of healthy food, disease, and death, water pollution often leads to a persistent shortage of clean drinking water accessible around the world (2).…”