Pollutant Removal from Synthetic Aqueous Solutions with a Combined Electrochemical Oxidation and Adsorption Method

Abstract

Eliminating organic and inorganic pollutants from water is a worldwide concern. In this study, we applied electrochemical oxidation (EO) and adsorption techniques to eliminate ammonia, phenols, and Mo(VI) from aqueous solutions. We analyzed the first stage (EO) with response surface methodology, where the reaction time (1–3 h), initial contaminant concentration (10–50 mg/L), and pH (3–6) were the three independent factors. Sodium sulfate (as an electrolyte) and Ti/RuO2–IrO2 (as an electrode) were used in the EO system. Based on preliminary experiments, the current and voltage were set to 50 mA and 7 V, respectively. The optimum EO conditions included a reaction time, initial contaminant concentration, and pH of 2.4 h, 27.4 mg/L, and 4.9, respectively. The ammonia, phenols, and Mo elimination efficiencies were 79.4%, 48.0%, and 55.9%, respectively. After treating water under the optimum EO conditions, the solution was transferred to a granular composite adsorbent column containing bentonite, limestone, zeolite, cockleshell, activated carbon, and Portland cement (i.e., BAZLSC), which improved the elimination efficiencies of ammonia, phenols, and molybdenum(VI) to 99.9%. The energy consumption value (8.0 kWh kg−1 N) was detected at the optimum operating conditions.

Cross-Linked Magnetic Chitosan/Activated Biochar for Removal of Emerging Micropollutants from Water: Optimization by the Artificial Neural Network

“…where corresponds the mass of adsorbate adsorbed/unit mass of adsorbent (mg adsorbate per g adsorbent), a and b denote empirical constants, and Ce denotes the equilibrium concentration of the adsorbate in the solution following adsorption (mg/L) [27]. Table 4 and Figure 10 display the details of the Langmuir isotherm studies.…”

“…where Kf is a fixed variable representing the relative adsorption capability of the adsorbent (mg 1−(1/n) /L 1/n /g −1 ), and n is a fixed variable signifying adsorption intensity [27]. Table 4 and Figure 11 display the details of the Freundlich isotherm studies.…”

Assessments of the Ecological and Health Risks of Potentially Toxic Metals in the Topsoils of Different Land Uses: A Case Study in Peninsular Malaysia

“…There is a probability of non-carcinogenic effects having a positive connection with the increment of the HI value [22]. The HI was calculated according to Equation (9).…”

“…The pollution of environments by heavy metals is a global issue, as rapid industrialization worldwide has significantly contributed to the release of theoretically potentially toxic metals (PTMs) into soils and water [ 8 , 9 ]. The elevated levels of PTMs in the topsoils of the different land uses may cause the weakening of the soil biological system, undermine human wellbeing, and create many environmental issues.…”

Appealing Renewable Materials in Green Chemistry

“…Zeolites, carbon, peat, and many other materials have proved to be particularly effective in eliminating pollutants from soil, air, and waters [ 6 , 7 ]. Furthermore, many electrochemical processes could be used as well [ 8 , 9 ].…”