A novel approach to developing a reusable marine macro-algae adsorbent with chitosan and ferric oxide for simultaneous efficient heavy metal removal and easy magnetic separation.

Chitosan modified magnetic kelp biochar (Chi-KBm) was successfully synthesized for efficient removal of heavy metals (Cu2+) from wastewater. Interestingly, the characterization results indicated that Chi-KBm showed 6 times higher surface area (6.17 m2/g) than the pristine magnetic kelp biochar KBm (0.97 m2/g). In addition, new functional groups, such as NH and CN group, have been created on the surface of biochar as a result of chitosan modification process, which in turns led to improve the Cu2+ adsorption capacity. The effect of pH and chitosan loading on heavy metal adsorption, and competition reaction of different metal ions adsorption were also investigated. Chi-KBm exhibited a separation efficiency of more than 99.8%, which allows to recovery and reusability of the adsorbent material and heavy metals simultaneously. Overall, this study highlighted the Chi-KBm is a promise adsorbent for heavy metal removal without sacrificing of the separation ability using magnetism.

Non-selective rapid electro-oxidation of persistent, refractory VOCs in industrial wastewater using a highly catalytic and dimensionally stable IrPd/Ti composite electrode.

Volatile organic compounds (VOCs) are highly toxic contaminants commonly dissolved in industrial wastewater. Therefore, treatment of VOC-containing wastewater requires a robust and rapid reaction because liquid VOCs can become volatile secondary pollutants. In this study, electro-oxidation with catalytic composite dimensionally stable anodes (DSAs)-a promising process for degrading organic pollutants-was applied to remove various VOCs (chloroform, benzene, toluene, and trichloroethylene). Excellent treatment efficiency of VOCs was demonstrated. To evaluate the VOC removal rate of each DSA, a titanium plate, a frequently used substratum, was coated with four different highly electrocatalytic composite materials (platinum group metals), Ir, IrPt, IrRu, and IrPd. Ir was used as a base catalyst to maintain the electrochemical stability of the anode. Current density and electrolyte concentration were evaluated over various ranges (20-45 mA/cm2 and 0.01-0.15 mol/L as NaCl, respectively) to determine the optimum operating condition. Results indicated that chloroform was the most refractory VOC tested due to its robust chemical bond strength. Moreover, the optimum current density and electrolyte concentration were 25 mA/cm2 and 0.05 M, respectively, representing the most cost-effective condition. Four DSAs were examined (Ir/Ti, IrPt/Ti, IrRu/Ti, and IrPd/Ti). The IrPd/Ti anode was the most suitable for treatment of VOCs presenting the highest chloroform removal performance of 78.8%, energy consumption of 0.38 kWh per unit mass (g) of oxidized chloroform, and the least volatilized fraction of 4.4%. IrPd/Ti was the most suitable anode material for VOC treatment because of its unique structure, high wettability, and high surface area.