Co-presence of fluoride (F-) and nitrate (NO3-) in water causes numerous health complications. Thus, they should be eliminated by an appropriate method like the EC process. In this research, simultaneous removal of F- and NO3- from synthetic aqueous solution and groundwater has been considered by the EC technique under operational parameters like anode materials (un-coated (Al and Fe) and synthesized coated (Ti/TiRuSnO2 and Ti/PbO2)), cathode materials (Cu, St, and Gr), current density (12, 24, and 36 mA/cm2), inter-electrode distance (0.5, 1, and 2 cm), pH (5.5, 7, and 8.5), NaCl concentrations (0.5, 1, and 1.5 g/L), electrolysis time (15, 30, 45, 60, 90, and 120 min), NO3- concentrations (75, 150, and 225 mg/L), and F- concentrations (2, 4, 6, and 8 mg/L) for the first time in this research. The results proved that Al as non-coated anode and Cu as cathode electrodes were more effective in the co-removal of F- and NO3-. The maximum removal efficiencies of 94.19 and 95% were observed at the current density of 36 mA/cm2, 1 cm of inter-electrode distance, pH 7, 1 g/L of NaCl, and 90 min electrolysis time by Al-Cu electrode for F- (2 mg/L) and NO3- (75 mg/L), respectively. The higher efficiency of Al-Cu electrodes was due to the simultaneous occurrence of electrocoagulation, electroreduction, and electrooxidation processes. Al-Cu electrode application considerably diminished f- and NO3- concentrations in the groundwater. Health risk assessment proved that HQ of F- was significantly decreased after treatment by the Al-Cu electrode. Thus, the EC process using an appropriate and effective electrode is a promising technique for treating aqueous solutions containing F- and NO3-. 

Simultaneous removal of fluoride and nitrate from synthetic aqueous solution and groundwater by the electrochemical process using non-coated and coated anode electrodes: A human health risk study.

The role of the current waveform in mitigating passivation and enhancing electrocoagulation performance: A critical review.

Comprehensive understanding of electrochemical treatment systems combined with biological processes for wastewater remediation.

Arsenic is a toxic and carcinogenic metalloid widely distributed in nature. It can enter water bodies through natural or man-made routes, posing a serious threat to the ecological environment and human health. In recent years, arsenic pollution in water has become a global problem. This study introduces the utilization of andradite from scheelite flotation tailings as a potential material for As(III) removal. The experimental results showed that after 30 min of milling, 5 g/L andradite achieved a removal rate of over 90 % for As(III), reducing its concentration from 1 mg/L to 0.09 mg/L. Scanning electron microscopy with energy dispersive spectrometry (SEM-EDS) and X-ray photoelectron spectroscopy (XPS) were carried to reveal the underlying mechanism of As(III) removal with andradite. Results indicated that the calcium atom and iron atom on the surface of andradite may react with As(III) to form calcium arsenite and ferric arsenite, and the products adhere to the surface of andradite. Based on the obtained results, andradite is a promising material for the remediation of arsenic pollution. Moreover, the source of andradite is very wide, and the cost of extraction and preparation is low. The extraction of andradite from non-ferrous metal flotation tailings as an adsorbent to remove As(III) not only improves the utilization rate of tailings resources, but also provides a new method for the prevention and control of arsenic pollution. 

Extraction of andradite from flotation tailings as a potential material for As(III) removal from simulated wastewater

Among the contaminants found in groundwater, arsenic poses a great threat to human health and the ecosystem. Therefore, it is vital to eliminate arsenic from water sources. This study utilizes one of the most efficient and emerging decontamination techniques known as the sono-electrocoagulation method. In recent years, sono-electrocoagulation has attracted many scientists due to its unique features, such as being cost-effective, rapid process, and high efficiency. The required groundwater samples were artificially synthesized in the laboratory, where the anode and cathode were determined to be Fe, Ti/PbO2, and Al, respectively. During the experiment, the impact of pH (5,6,7,8), various initial concentrations (100, 200, 300,400, 500, 600 μg/l), exposure times of 5,10,15,20,25 min, electrode distances of 1.5,2,2.5,3,3.5 cm and different current intensities of 5,10,15,20,25 mA/cm2 were examined. The ambient temperature of the laboratory was kept at 30 and 40 °C. Furthermore, this study showed that the system containing Ti/PbO2 as the anode and Al as the cathode electrodes removed arsenic contamination more effectively in the base environment. The performance of arsenic removal was directly related to current intensity, pH, and time. Nevertheless, time elapse played a negative factor due to the corrosion of the electrodes' surface and the dissolution of floating materials in the solution. With the surge of arsenic concentration from 100 to 300 mg/L, the arsenic removal efficiency increased from 61.9 to 98.5 percent, where the maximum removal efficiency due to the rise of the current intensity was 84.16 percent. The sono-electrocoagulation method reduced the risk of carcinogenic and non-carcinogenicity from 5.15E-03 to 7.73E-05 and 26.71 to 0.40. Accordingly, it was found that a combination of ultrasonic and electrocoagulation processes is a promising approach for arsenic removal. 

Application of sono-electrocoagulation in arsenic removal from aqueous solutions and the related human health risk assessment.

Abstract Diesel oil is known to be one of the major petroleum products that can pollute water and soil. Soil pollution caused by petroleum hydrocarbons has substantially impacted the environment, especially in the Middle East. In this study, modeling and optimization of hexadecane removal from soil was performed using two pure cultures of Acinetobacter and Acromobacter and consortium culture of both bacterial species using artificial neural network (ANN) method. Then the best ANN structure was proposed based on mean square error (MSE) as well as correlation coefficient (R) for pure cultures of Acinetobacter and Acromobacter as well as their consortium. The results showed that the correlations between the actual data and the data predicted by ANN (R2) in Acromobacter , Acinetobacter and consortium of both cultures were 0.50, 0.47 and 0.63, respectively. Despite the low correlation between the experimental data and the data predicted by the ANN, the correlation coefficient and the precision of ANN for the consortium was higher. As a result, ANN had desirable precision to predict hexadecan removal by the cobsertium culture of Ochromobater and Acintobacter . 

/pdf/modelling-of-n-hexadecane-bioremediation-from-soil-by-slurry-21agdewb.pdf

H. Mehrazmay

Papers

Application of sono-electrocoagulation in arsenic removal from aqueous solutions and the related human health risk assessment.

Modelling of n-Hexadecane bioremediation from soil by slurry bioreactors using artificial neural network method