Evaluation of dairy industry wastewater treatment and simultaneous bioelectricity generation in a catalyst-less and mediator-less membrane microbial fuel cell

Increased human activity and consumption of natural energy resources have led to decline in fossil fuel. These current methods of energy production are not compatible with the environment. In this study catalyst-less and mediator-less membrane microbial fuel cell (CAML-MMFC) represents a new method for simultaneous dairy industry wastewater treatment and bioelectricity generation. The CAML-MMFC used was designed as two chambered that included an anaerobic anode and aerobic cathode compartment and was separated from each other by a proton exchange membrane. The anode and cathode electrodes were made from graphite plate. Current intensity, power density and voltage produced from wastewater as fuel were measured and the effluent from the anode compartment was examined to evaluate pollutant decrease. The maximum current intensity and power density produced were respectively 3.74 mA and 621.13 mW/m2 on the anode surface, at OLR equal to 53.22 kgCOD/m3 d and at the external resistance of 1 k Ω. The maximum voltage produced was 0.856 V at OLR equal to 53.22 kgCOD/m3 d and at temperature 35oC. The maximum coulombic efficiency of 37.16 was achieved at OLR equal to 17.74 kgCOD/m3 d. The HRT was examined as a factor influencing the power generation and when it was 5 day, maximum voltage and power density were obtained. The maximum removal efficiency of COD, BOD5, NH3, NH4 +, dissolved phosphorus, phosphorus in suspended solids, SO4 2-, TSS, and VSS was respectively achieved at 90.46, 81.72, 73.22, 69.43, 31.18, 72.45, 39.43, 70.17 and 64.6. The results showed that generating bioelectricity and dairy industry wastewater treatment by CAML-MMFC are a good alternative for producing energy and treating wastewater at the same time. © 2014 King Saud University. Production and hosting by Elsevier B.V

Efficiency of multi walled carbon nanotubes for removing Direct Blue 71 from aqueous solutions

Dye wastewater produced from industrial activity is usually toxic, resistant to biodegradation and persistent in the environment. The aim of this study was to evaluate the efficiency of multiwalled carbon nanotubes (MWCNTs) for decolorization of Direct Blue 71 (DB71). In this experimental study, the effect of various variables including contact time, solution pH, adsorbent dose, and initial dye concentration was evaluated in a batch reactor. The adsorption and kinetic models were evaluated to explain the adsorbed dye and dynamic reaction. The results of this study showed that the efficiency of dye removal increased, as the contact time and adsorbent dose increased, but as pH and initial dye concentration increased, removal efficiency decreased. The maximum efficiency of Direct Blue 71 removal was observed at acidic solution (pH=3), contact time of 90 minutes, adsorbent dose of 0.6 g/l and initial dye concentration of 25 mg/l. The adsorption of direct blue 71 best fitted the Langmuir isotherm (R2=0.87) and pseudo first order kinetic equation (R2=0.99). According to the results obtained, multiwalled nanotubes was offered as an effective adsorbent for removing direct blue 71. © Authors

Efficiency of multi walled carbon nanotubes for removing Direct Blue 71 from aqueous solutions

Dye wastewater produced from industrial activity is usually toxic, resistant to biodegradation and persistent in the environment. The aim of this study was to evaluate the efficiency of multiwalled carbon nanotubes (MWCNTs) for decolorization of Direct Blue 71 (DB71). In this experimental study, the effect of various variables including contact time, solution pH, adsorbent dose, and initial dye concentration was evaluated in a batch reactor. The adsorption and kinetic models were evaluated to explain the adsorbed dye and dynamic reaction. The results of this study showed that the efficiency of dye removal increased, as the contact time and adsorbent dose increased, but as pH and initial dye concentration increased, removal efficiency decreased. The maximum efficiency of Direct Blue 71 removal was observed at acidic solution (pH=3), contact time of 90 minutes, adsorbent dose of 0.6 g/l and initial dye concentration of 25 mg/l. The adsorption of direct blue 71 best fitted the Langmuir isotherm (R2=0.87) and pseudo first order kinetic equation (R2=0.99). According to the results obtained, multiwalled nanotubes was offered as an effective adsorbent for removing direct blue 71. © Authors

Drinking water softening with electrocoagulation process: Influence of direct and alternating currents as inductive with different arrangement rod electrodes and polarity inverter

This study investigates the process of electrocoagulation with direct and alternating currents as inductive using Fe and Al rods with different arrangements and a polarity inverter and based on the factors related to the efficacy of the process for drinking water softening. The efficacy of the electrocoagulation (EC) process was investigated in the batch mode under different conditions. Further, the amount of energy and electrode consumption and the amount of sludge produced were determined. Total hardness (98.26) and calcium hardness (87.69) were reduced with the highest efficiency using alternating current with Fe-Al electrode arrangement under optimal conditions (pH of 9, current density of 9 m A / c m 2, and electrolysis time of 12 min). Optimum charge loading was 0.54F/m3. Maximum energy and electrode were consumed at the optimum current density using direct current, which were measured at 2.47 k W h / m 3 and 2.12 k g / m 3, respectively Maximum sludge was produced at optimum current density using alternating current of 0.098 k g / m 3 with the settleability of 0.075 L/g and, also, usine: direct current of 0.109 k g / m 3 with the settleability of 0.063 L/g. This study showed that through the alternating current and using Fe electrodes, EC technology could be used as an alternative, new method for reducing water hardness with high efficiency and low energy consumption. © 2020 Sharif University of Technology. All rights reserved