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Chitosan is an efficient metal chelater, but its practical use is limited due to the stability in acid solutions, adsorption capacities. In this study, we attempt to find a new pH-dependent adsorbent based on fructose-mediated chitosan/PEG membrane and examines several experimental parameters relative to their formation and characteristics. The membrane was characterized in terms of their fourier transforms infrared spectroscopy-attenuated total reflectance (FTIR-ATR) spectra, X-ray diffraction (XRD) analysis, surface morphologies, tensile strength, mediating degree analysis, and swelling behavior at pH 3 and 6 medium. To estimate the potential of these membranes as a biosorbent, the capability and behavior for the adsorption of heavy metal ions were investigated using Lead ions as a model compound. FTIR-ATR result showed that the Schiff's base reaction was favor formed in high pH condition. Swelling study showed that the swelling degree of homogeneous mediated membrane decreases as the pH of the final fructose-mediated chitosan/PEG gel increase, which was demonstrated by mediating degree analysis. Low crystallinity of fructose-mediated membranes is responsible for its sorption efficiency. With increasing the amount of fructose in the chitosan/PEG there is a proportionality of the adsorption capacity except that the high fructose content (10 wt %). The pH 6 treated 5 wt % fructose-mediated membrane has a maximum sorption capacity to about 185 mg/g. The adsorption isotherms could be well fitted by the Langmuir equation. The results showed the potential applicability of fructose-mediated chitosan/PEG membrane as a biosorbent for metal recovery.

Valuable metal materials can be recovered from spent nickel-metal hydride (NiMH) batteries. However, little attention has been paid to the metal compositions of individual components of NiMH batteries, although this is important for the selection of the appropriate recycling process. In this study, NiMH batteries were manually disassembled to identify the components and to characterize the metals in each of these. A preliminary economic analysis was also conducted to evaluate the recovery of valuable metals from spent NiMH batteries using thermal melting versus simple mechanical separation. The results of this study show that metallic components account for more than 60% of battery weight. The contents of Ni, Fe, Co, and rare earth elements (REEs) (i.e., valuable metals of interest for recovery) in a single battery were 17.9%, 15.4%, 4.41%, and 17.3%, respectively. Most of the Fe was in the battery components of the steel cathode collector, cathode cap, and anode metal grid, while Ni (>90%) and Co (>90%) were mainly in the electrode active materials (anode and cathode metal powders). About 1.88 g of REEs (Ce, La, and Y) could be obtained from one spent NiMH battery. The estimated profits from recovering valuable metals from spent NiMH batteries by using thermal melting and mechanical processes are 2,329 and 2,531 USD/ton, respectively, when including a subsidy of 1,710 USD/ton. The findings of this study are very useful for further research related to technical and economic evaluations of the recovery of valuable metals from spent NiMH batteries.Implications: The spent nickel-metal hydride (NiMH) batteries were manually disassembled and their components were identified. The metals account for more than 60% of battery weight, when Ni, Fe, Co, and rare earth elements (REEs) were 17.9%, 15.4%, 4.41%, and 17.3%, respectively, in a single battery. The estimated profits of recovering valuable metals from NiMH batteries by using thermal melting and mechanical processing are 2,329 and 2,531 USD/ton, respectively, when including a subsidy of 1,710 USD/ton. These findings are very useful to develop or select the recovery methods of valuable metals from spent NiMH batteries.PAPER HISTORY

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