Selective Chelating Resin for Copper Removal and Recovery in Aqueous Acidic Solution Generated from Synthetic Copper-Citrate Complexes from Bioleaching of E-waste

This research focused on batch experiment using a new generation of chelating resins via an ion exchange process to describe the metabolic adsorption and desorption capacity onto iminodiacetic acid/Chelex 100, bis-pyridylmethyl amine/Dowex m4195, and aminomethyl phosphonic/Lewatit TP260 functional groups in bioleaching. The results showed that Dowex m4195 had the highest performance of adsorption capacity for copper removal in both H+-form and Na+-form. Results for Lewatit TP260 and Chelex 100 revealed lower adsorption performance than results for Dowex m4195. The investigation of desorption from chelating resins was carried out, and it was found that 2 M ammonium hydroxide concentration provided the best desorption capacity of about 64.86% for the H+-form Dowex m4195 followed by 52.55% with 2 M sulfuric acid. Lewatit with 2 M hydrochloric acid gave the best desorption performance in Na+-form while Chelex 100 using hydrochloric at 1 M and 2 M provided similar results in terms of the H+-form and Na+-form. As aspects of the selective chelating resins for copper (II) ions in aqueous acidic solution generated from synthetic copper-citrate complexes from bioleaching of e-waste were considered, H+-form Dowex m4195 was a good performer in adsorption using ammonium hydroxide for the desorption. However, chelating resins used were subsequently reused for more than five cycles with an acidic and basic solution. It can be concluded from these results that selective chelating resins could be used as an alternative for the treatment of copper (II) ions contained in e-waste or application to other divalent metals in wastewater for sustainable water and adsorbent reuse as circular economy.

Effect of magnetite on alginate-based hydrogel beads composite bio-sorbent for copper removal

A composite magnetite alginate-based bio-sorbent in hydrogel beads form as adsorbent for copper ion removal was prepared through this work. Two types of composite bio-sorbents which are cellulose-magnetite-alginate (CeMA) and chitosan-magnetite-alginate (CMA) hydrogel beads were synthesized by the physical cross-linking method. Ratios of magnetite iron oxide 0, 0.1, and 1.0 were used during the synthesis of bio-sorbents to observe the effect of magnetite ratios on copper ion removals. Based on the performance of bio-sorbents on copper removals, 24.6% of the highest percentage copper removal was achieved by CMA with a magnetite ratio of 0.1 at an adsorption equilibrium time of 24 hours and initial concentration of 100 mg/L. In addition, through this work, magnetite embedded bio-sorbent with the simple synthesized method was done by utilizing the capability of alginate to instantaneously form hydrogel beads upon addition into calcium chloride (Ca2+). Therefore, this work proves the potential of magnetite embedded in alginate-based composite bio-sorbent hydrogel beads for heavy metal industrial wastewater.