Highlights A sulfuric acid leaching process is applied on unsorted spent batteries. The pregnant leach solution (PLS) contains Zn, Mn, Cd, Ni and Co. Zn and Cd are separated from PLS using solvent extraction and electrodeposition. Mn and Ni are recovered using chemical precipitation as metal carbonates. AbstractThis investigation presents the development of a waste batteries recycling technology, that could lead to the minimization of waste discharged and contamination problems and to the depletion of natural resources. This study mainly focused on the recovery of metals from a pregnant leach solution (PLS) obtained from a sulphuric leaching process applied to unsorted spent batteries. The PLS mainly contains Zn, Mn, Cd, Ni and Co. Cyanex 272 (di-2,4,4trimethylpentyl phosphinic acid) was used to selectively recover Zn from the mixed solution.The Zn-Cyanex 272 was stripped and electrodeposited in metallic form and approximately 134 kg of Zn were recovered. Cd and Mn were co-extracted in the organic solvent D2EHPA (2ethylhexylphosphonic acid) from the Zn-depleted solution and they were stripped using H 2 SO 4 .Consequently, Cd was selectively electrodeposited from a sulphate-stripped solution where the amount of Cd recovered was equal to 21.6 kg Cd per ton of waste battery powder. Residual Mn was recovered in the carbonate form by the addition of Na 2 CO 3 (238 kg of Mn t -1 of waste battery powder). In the following step, Cyanex 272 was used to remove Co and other impurities from the Zn-Cd-Mn depleted solution, while Ni was not extracted. Finally, Ni was precipitated from the pure NiSO 4 solution with Na 2 CO 3 and 23.8 kg of Ni were recovered per ton of waste battery powder. The costs of the process develop to recover metals (including only chemical costs and energy consumption) are estimated at $814 t -1 of battery powder, while the metal revenues obtained are estimated at $2,132 t -1 of battery powder. The chemical cost /metal revenue ratio is lower than 50%, which indicates that the process is feasible.

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River water samples were taken from 32 locations around the basin of Chaophraya River and its four major tributaries in Thailand to investigate resistance ratios of Escherichia coli isolates to eight antibiotic agents of amoxicillin, sulfamethoxazole/trimethoprim, tetracycline, doxytetracycline, ciprofloxacin, levofloxacin, norfloxacin and ofloxacin. Principal component analysis was performed to characterize resistance patterns of the samples. Relevancy of the obtained principal components with urban land use and fecal contamination of the river were examined. The ratio of antibiotic-resistant bacteria is likely to increase when urban land use near the sampling site exceeds a certain ratio. The resistance ratio to fluoroquinolones tends to be high in a highly populated area. Meanwhile, no significant contribution of fecal contamination was found to increase the resistance ratio. These results suggest that an antibiotic-resistance ratio is dependent on conditions of local urbanization rather than the upstream conditions, and that the major sources of antibiotic-resistant bacteria in the Chaophraya River basin are possibly point sources located in the urban area which contains a high ratio of resistant bacteria.

This paper presents an innovative process for the recovery of valuable metals from a mixture of spent batteries. Different types of batteries, including alkaline, zinc-carbon (Zn-C), nickel cadmium (Ni-Cd), nickel metal hydride (Ni-MH), lithium ion (Li-ion) and lithium metallic (Li-M) batteries, were mixed according to the proportion of the Canadian sales of batteries. A Box-Behnken design was applied to find the optimum leaching conditions allowing a maximum of valuable metal removals from a mixture of spent batteries in the presence of an inorganic acid and a reducing agent. The results highlighted the positive effect of sodium metabisulfite on the performance of metals removal, especially for Mn. The solid/liquid ratio and the concentration of HSO were the main factors affecting the leaching behavior of valuable metals (Zn, Mn, Cd, Ni) present in spent batteries. Finally, the optimum leaching conditions were found as follows: one leaching step, solid/liquid ratio = 10.9%, [HSO] = 1.34 M, sodium metabisulfite (NaSO) = 0.45 g/g of battery powder and retention time = 45 min. Under such conditions, the removal yields achieved were 94% for Mn, 81% for Cd, 99% for Zn, 96% for Co and 68% for Ni.