Integration of Fenton Oxidation with Nano-Graphene Oxide to Eliminate the Hazardous Effect of Chromated/Dyed Tannery Effluents

Abstract

Effective management of tannery effluent is needed for this time. Tanning industry is one of the worst industries from an environmental point of view, where is the prominent sources of pollution to the aquatic environment. Wetfinishing effluent is the most dangerous step, which generate the obnoxious effluent in the tanning industry. The conventional treatments of such waste showed deficiency to coop with the required limits of national regulatory standards. In the present study, an advanced oxidation technique based on modification of Fenton reaction combined with high porous nanomaterials was applied as an alternative treatment. Variable doses of H2O2, Fe +2 , CaO and pH were investigated to determine the optimum operating conditions. The obtained results indicated a good quality of the treated effluent. Residual concentrations of COD, BOD and TSS were 98.51%, 98.11% and 98.82% removal, respectively. The most obnoxious material (Cr) was highly removed (98.92%). Also, decolourization value (YCOL values) was obtained using Nano GO (99%) and/or active charcoal (88.08 %) with CaO. The residual effect of H2O2 was reduced by MnO2, SnO and Fe powder than sod. thiosulphate. The treated effluent could meet to the National regulatory standard for discharging into the sewerage systems with respect to the studied parameters.

Analysis of the Capacity of the Fenton Process for the Treatment of Polluted Wastewater from the Leather Dyeing Industry

“…Regarding the efficiency of the treatment used for the degradation of dyes in a similar range of concentrations (e.g., concentration of dye and/or COD), similar results were obtained by both Bravo-Yumi et al [ 71 ], who applied electro-Fenton and photoelectro-Fenton for the treatment of synthetic effluents polluted with the mixture of dyes (Violet RL-Green A), and by Lofrano et al [ 36 ], who used photo-Fenton for the treatment of effluent containing syntan. Likewise, the novel Fenton oxidation, which applied the combination of Fe 2+ , H 2 O 2 , CaO, and graphene nano-oxide, was very effective for the treatment of an industrial tannery effluent [ 14 ]. However, a lack of information on the operating costs of those FOP treatments applied for both industrial and synthetic (simulated) tanning effluents makes fair comparison difficult.…”

“…Tese present a series of bars whose extensions refect the frequency or impact of each factor (e.g., the longer the bar is, the greater the infuence and efect of the factor on the response variable), regardless of whether the efect is positive (increasing the efect will cause an increase in the response variable) or negative (increasing the efect will cause a decrease in the 4). Te percentage efect of each factor on the response variable was calculated using equation (14), where b i corresponds to the value of the standardized efect for factor i [38].…”

“…In addition, biological (or secondary) processes are inefficient due to the low biodegradability of WWDS (in general, the (biochemical oxygen demand)/(chemical oxygen demand) ratio BOD 5 /COD is <0.4) and the presence of metals [ 13 ]. On the other hand, advanced oxidation processes (AOPs) are becoming emerging alternatives for the treatment of this type of wastewater [ 14 ] and effluents polluted with insecticides [ 15 ], chemicals used in plastics manufacturing [ 16 ], antibiotics [ 17 , 18 ], azo dyes [ 19 ], and sewage sludge [ 20 ]. These processes are based on the production of the hydroxyl radical (HO • ) (i.e., a short-lived, nonselective, and highly reactive oxidizing agent) that allows the mineralization of almost any organic and organometallic contaminant [ 21 ].…”

“…However, to the best of our knowledge, it has not been used in the treatment of wastewater from the tannery industry. In most of the studies reported in the open literature for the treatment of tanning wastewater by FOP, the authors used synthetic (simulated) wastewater (i.e., dissolving dye in distilled water) [ 14 , 35 , 36 ]. Only a few reports can be found on the conventional Fenton application for industrial WWDS.…”

“…Only a few reports can be found on the conventional Fenton application for industrial WWDS. Among them, Alashkar et al [ 14 ] successfully implemented the homogeneous Fenton process to treat a highly contaminated WWDS (i.e., COD = 13120 mg O 2 /L, BDO 5 = 6300 mg O 2 /L, and Cr = 260 mg/L) reaching COD and BDO 5 removals of 99 and 98%, respectively. Unfortunately, in this work, no toxicity studies were performed nor were operating conditions optimized to reduce operating costs and maximize organic load removal.…”