Selective recovery of copper from copper tailings and wastewater using chelating resins with bis-picolylamine functional groups

Industrial and mining wastewater, along with copper tailings, are typically highly acidic and contain copper and other heavy metals, which may contaminate and damage the environment. Copper (Cu) is, however, a valuable metal, making its removal and recovery from such wastewater and tailings environmentally and economically advantageous. Chelating ion exchange resins featuring bis-picolylamine functional groups are especially suitable for application requiring selective recovery of Cu(II) from highly acidic media. In this study, and for the first time, the kinetics, binding capacity and selectivity of Lewatit MDS TP 220 chelating resin towards Cu(II) are reported. The resin was characterized by Zeta potential, scanning electron microscope (SEM), Fourier-transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS). Factors including pH, initial concentration, contact time, temperature, and selectivity were investigated to assess the adsorption performance of the chelating resin. The adsorption kinetics tests revealed fast adsorption within the first 5-30 min and fitted the pseudo-second-order model, signifying chemisorption process. The adsorption isotherm followed the Langmuir model, implying monolayer adsorption process. The maximum adsorption capacity (qm) for Cu(II) determined by the Langmuir model was 103.9 mg/g. The adsorption thermodynamics showed an endothermic and spontaneous adsorption. FTIR and XPS studies suggested coordination or chelation as the possible adsorption mechanism. Lewatit MDS TP 220 exhibited excellent Cu(II) adsorption, desorption with 2 M ammonium hydroxide (NH4OH), and selectivity in multi-metal ions solution. Additionally, the resin demonstrated excellent reusability after five regeneration steps. This chelating resin is a potential adsorbent for effective and recurrent recovery of Cu(II) from copper tailings and wastewater, thereby contributing to environmental remediation.

New Chelate Resins Prepared with Direct Red 23 for Cd2+, Ni2+, Cu2+ and Pb2+ Removal

In this paper, two chelate resins prepared by a simple procedure were used for the removal of Cd2+, Ni2+, Cu2+, and Pb2+ (M2+) from aqueous solutions. Amberlite IRA 402 strongly basic anion exchange resin in Cl− form (IRA 402 (Cl−) together with Amberlite XAD7HP acrylic ester co-polymer (XAD7HP) were functionalized with chelating agent Direct red 23 (DR 23). The chelate resins (IRA 402-DR 23 and XAD7HP-DR 23) were obtained in batch mode. The influence of interaction time, pH and the initial concentration of DR 23 solution was investigated using UV-Vis spectrometry. The time necessary to reach equilibrium was 90 min for both resins. A negligible effect of adsorption capacity (Qe) was obtained when the DR 23 solution was adjusted at a pH of 2 and 7.9. The Qe of the XAD7HP resin (27 mg DR 23/g) is greater than for IRA 402 (Cl−) (21 mg DR 23/g). The efficiency of chelating resins was checked via M2+ removal determined by the atomic adsorption spectrometry method (AAS). The M2+ removal by the IRA 402-DR 23 and XAD7HP-DR 23 showed that the latter is more efficient for this propose. As a consequence, for divalent ions, the chelated resins followed the selectivity sequence: Cd2+ > Cu2+ > Ni2+ > Pb2+. Additionally, Cd2+, Cu2+ and Ni2+ removal was fitted very well with the Freundlich model in terms of height correlation coefficient (R2), while Pb2+ was best fitted with Langmuir model for IRA 402-DR 23, the Cu2+ removal is described by the Langmuir model, and Cd2+, Ni2+ and Pb2+ removal was found to be in concordance with the Freundlich model for XAD7HP-DR 23. The M2+ elution from the chelate resins was carried out using 2 M HCl. The greater M2+ recovery from chelating resins mass confirmed their sustainability. The chelate resins used before and after M2+ removal by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) analysis were evaluated.

Characterization and Optimization of Polymeric Bispicolamine Chelating Resin: Performance Evaluation via RSM Using Copper in Acid Liquors as a Model Substrate through Ion Exchange Method

Advanced technologies of electronics industries have led to environmental contamination concerns, especially waste print circuit boards containing a very high concentration of copper (II) ions, which can be discharged in wastewater containing many contaminated metals. A low pH is a necessity for treating industrial wastewater containing heavy metals to meet engineering process design. A novel polymeric bispicolamine chelating resin, Dowex-M4195, was applied as an alternative for investigating the behavior of copper (II) in acidic solution via an ion exchange method in a batch experiment system. Characterization of physical and chemical properties before and after ion exchange were also explored through BET, SEM-EDX, FTIR and XRD. Response surface methodology was also applied for optimization of copper (II) removal capacity using design of experiment for selective chelating resin at a low pH. The results indicate that H+ Dowex-M4195 chelating resin had a high-carbon content and specific surface area of >64% and 26.5060 m2/g, respectively. It was predominantly macropore porous in nature due to the N2 gas adsorption isotherm and exhibited type IV with insignificant desorption hysteresis loop of H1-type. It was spherical and cylindrical. After the ion exchange process of copper (II)-loaded H+ Dowex-M4195, the specific surface area and total pore volume decreased by about 17.82% and 5.39%, respectively, as compared to H+ Dowex-M4195. Hysteresis loop, isotherm and pore size distribution were also similar. Regarding the functional group, the surface morphology and crystalline structures of H+ Dowex-M4195 showed copper (II) compound based on the structure of chelating resin that confirmed effective ion exchange behavior. The design of optimization indicated that copper (II) removal capacity of about 31.33 mg/g was achieved, which could be obtained at 6.96 h, pH of 2 (a desirable low pH), dose of 124.13 mg and concentration of 525.15 mg/L. The study indicated that the H+ Dowex-M4195 (which is commercially available on the market) can successfully be applied as an alternative precursor through the ion exchange method for further reuse and regeneration of the copper (II) in the electronic waste industries and other wastewater applications needed to respond the policy of biocircular green economy in Thailand.

Natural and Synthetic Polymers Modified with Acid Blue 113 for Removal of Cr3+, Zn2+ and Mn2+

This research had two stages of development: during the first stage, the purpose of the research was to evaluate the adsorption properties of the natural polymer represented by shredded maize stalk (MS) and by Amberlite XAD7HP (XAD7HP) acrylic resin for removal of toxic diazo Acid Blue 113 (AB 113) dye from aqueous solutions. The AB 113 concentration was evaluated spectrometrically at 565 nm. In the second stage, the stability of MS loaded with AB 113 (MS-AB 113) and of XAD7HP loaded with AB 113 (XAD7HP-AB 113) in acidic medium suggests that impregnated materials can be used for selective removal of metal ions (Cr³⁺, Zn²⁺ and Mn²⁺). The metal ions using atomic absorption spectroscopy method (AAS) were determined. The use of MS-AB 113 ensures a high selectivity of divalent ions while the XAD7HP-AB 113 had excellent affinity for Cr³⁺ in the presence of Zn²⁺ and Mn²⁺. As a consequence, two advanced polymers, i.e., MS-AB 113 and XAD7HP-AB 113 that provide huge capacity for removal of Zn²⁺, Mn²⁺ and Cr³⁺ from acid polluted wastewater were obtained.