Spent Li-ion batteries (LIBs) are highly rich in cobalt and lithium that need to be recovered to reduce shortages of these valuable metals and decrease their potential environmental risks. This study applied bioleaching using Aspergillus niger strains MM1 and SG1 and Acidithiobacillus thiooxidans 80191 for removal of Co and Li from spent LIB under type 1 and type 2 conditions. Moreover, metal recovery was attempted from the fungal leaching solution by sodium sulfide, sodium hydroxide, and sodium oxalate for Co and then for Li using sodium carbonate. The findings of this work show that metal removal in fungal bioleaching under type 2 system was highly comparable or even better than bacterial or acid leaching. A significant quantity of Co (82%) and Li (100%) dissolution was observed in strain MM1; however, metal solubilization was poor in strain 80191 because only 22% Co and 66% Li solubilized. A high amount of Co precipitated potentially as cobalt sulfide (100%), cobalt hydroxide (100%), or cobalt oxalate (88%), whereas Li precipitated as lithium carbonate (73.6%). Finally, results of this study suggest that fungal bioleaching could be an environmentally friendly approach for solubilization and recovery of considerable quantities of metals from spent LIBs.

The recovery of precious metals from waste printed circuit boards (PCBs) is an effective recycling process. This paper presents a promising hydrometallurgical process to recover precious metals from waste PCBs. To simplify the metal leaching process, large pieces of PCBs were used instead of a pulverized sample. The chemical coating present on the PCBs was removed by sodium hydroxide (NaOH) treatment prior to the hydrometallurgical treatment. Among the leaching reagents examined, hydrochloric acid (HCl) showed great potential for the recovery of metals. The HCl-mediated leaching of waste PCBs was investigated over a range of conditions. Increasing the acid concentration decreased the time required for complete metal recovery. The shaking speed showed a pronounced positive effect on metal recovery, but the temperature showed an insignificant effect. The results showed that 1 M HCl recovered all of the metals from 4 cm × 4 cm PCBs at room temperature and 150 rpm shaking speed in 22 h.

Aims:  To isolate the potential micro‐organism for the degradation of textile disperse dye Brown 3 REL and to find out the reaction mechanism. Methods and Results:  16S rDNA analysis revealed an isolate from textile effluent contaminated soil as Bacillus sp. VUS and was able to degrade (100%) dye Brown 3REL within 8 h at static anoxic condition. A significant increase in the activities of lignin peroxidase, laccase and NADH‐DCIP reductase was observed up to complete decolourization of Brown 3REL. The optimum temperature required for degradation was 40°C and pH 6·5–12·0. Phyto‐toxicity and chemical oxygen demand revealed nontoxic products of dye degradation. The biodegradation was monitored by UV–VIS, FTIR spectroscopy and HPLC. The final products 6,8‐dichloro‐quinazoline‐4‐ol and cyclopentanone were characterized by gas chromatography‐mass spectrometry. This Bacillus sp. VUS also decolourized (80%) textile dye effluent within 12 h. Conclusions:  This study suggests that Bacillus sp. VUS could be a useful tool for textile effluent treatment. Significance and Impact of the Study:  The newly isolated Bacillus sp. VUS decolourized 16 textile dyes and textile dye effluent also. It achieved complete biodegradation of Brown 3REL. Phytotoxicity study demonstrated no toxicity of the biodegraded products for plants with respect to Triticum aestivum and Sorghum bicolor.

No abstract

The plant's ethno-medicinal importance, antioxidant potential, inhibitory activity against the Aspergillus group of fungi and production of aflatoxins may add a new dimension to its usefulness in the protection of stored product.