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This research was carried out for two purposes. First, investigation of seven heavy metals concentrations in six supermarket vegetables in two seasons in Tehran, second, to estimate the potential h...

Photoelectro-Fenton was applied for the removal of acid yellow 36 (AY36) from synthetic aqueous solution using iron electrodes. A Box–Behnken design was used for optimization of the effects of pH, H2O2 concentration, current density, and reaction time. Individual effects of these variables were more important than their interaction effects. The derived model was in good agreement with the experimental results. Total organic carbon was determined in solution and sludge in order to clarify the removal mechanism. Increase of H2O2 concentration and current density led to domination of oxidation and coagulation mechanisms, respectively. The effects of scavenging and inhibiting agents were also investigated: (1) presence of alcohols can reduce the efficiency through competition with dye for reaction with hydroxyl radicals; (2) anions (NO3−, HCO3−, and H2PO4−) scavenged hydroxyl radicals and reduced decolorization of AY36.

Olive oil mill wastewater (OOMW) is a complex effluent that must be treated before discharge into the environment. In this study, a combination of various mechanisms was conducted in an electrochemical cell. Copper and PbO2 anodes were used, while hydrogen peroxide was electro-generated at an activated carbon fiber cathode. Fenton-like reaction and electrooxidation occurred during electrolysis for organic compounds degradation in OOMW. The effects of pH, dilution of OOMW, and electrical current on COD and phenol removals were investigated. The results showed that 78.5% phenol and 60% COD removals were obtained at optimum conditions of 300 mA electrical current, 150 min electrolysis, and pH 3–3.5 (regulated). The regulation of pH during electrolysis significantly developed the treatment efficiency of electrochemical process. Phenol and COD removal kinetics were likely to follow second-order model and first-order model, respectively. Simultaneous application of two anodes had synergic effect on remo...

Feasibility of RSM-optimized electrocoagulation (EC) sludge recycling was studied in photo-Fenton (PF) process for the removal of Direct Blue 71. By EC process, relatively complete decolorization was obtained in pH 8, 20 min, and 150 mA. The produced sludge, in EC process, was evaluated to be used and recycled in PF process experimental runs for two major targets: (1) Degradation of EC sludge as an environmental, concerning by-product; (2) Application of iron species resulted from anodic dissolution during EC process to play the role of catalyst in PF process. PF process was investigated based on the effects of EC sludge volume (total iron) and hydrogen peroxide concentration on decolorization. Besides, the effect of EC sludge recycling on decolorization and mineralization (TOC decrement) was studied. In optimum conditions of PF process (pH 3, 200 mg/L H2O2, 20 mL EC sludge and 30 min reaction time in the first run), 96.27% decolorization was achieved. In the same conditions, but in 10 min, 67.5% ...