Construction of lignin-based nano-adsorbents for efficient and selective recovery of tellurium (IV) from wastewater

Recent advances and future perspective on lignocellulose-based materials as adsorbents in diverse water treatment applications

The growing shortage of non-renewable resources and the burden of toxic pollutants in water have gradually become stumbling blocks in the path of sustainable human development. To this end, there has been great interest in finding renewable and environmentally friendly materials to promote environmental sustainability and combat harmful pollutants in wastewater. Of the many options, lignocellulose, as an abundant, biocompatible and renewable material, is the most attractive candidate for water remediation due to the unique physical and chemical properties of its constituents. Herein, we review the latest research advances in lignocellulose-based adsorbents, focusing on lignocellulosic composition, material modification, application of adsorbents. The modification and preparation methods of lignin, cellulose and hemicellulose and their applications in the treatment of diverse contaminated water are systematically and comprehensively presented. Also, the detailed description of the adsorption model, the adsorption mechanism and the adsorbent regeneration technique provides an excellent reference for understanding the underlying adsorption mechanism and the adsorbent recycling. Finally, the challenges and limitations of lignocellulosic adsorbents are evaluated from a practical application perspective, and future developments in the related field are discussed. In summary, this review offers rational insights to develop lignocellulose-based environmentally-friendly reactive materials for the removal of hazardous aquatic contaminants.

Efficient Separation and Purification Method for Recovering Valuable Elements from Bismuth Telluride Refrigeration Chip Waste

Bismuth telluride and its alloys are widely utilized in thermoelectric refrigeration and power generation devices. Waste bismuth telluride-based cooling chips contain valuable elements; however, recycling processes for these materials remain underdeveloped due to their complexity. In this study, we developed a concise and efficient chemical method that does not require expensive reagents or equipment, enabling the separation and purification of tellurium, bismuth, selenium, and antimony from waste bismuth telluride-based cooling chips. Initially, the waste was leached with HCl and NaClO3 to dissolve primary elements and recover 99.9% of selenium using hydroxylamine hydrochloride. Subsequently, Na2S and NaOH were employed for precipitation and leaching, resulting in a solution containing tellurium. The precipitated residue was treated with HNO3 to oxidize antimony into insoluble SbOHN and dissolve bismuth completely. 99.8% of the bismuth telluride waste was dissolved via oxidative leaching through hydrolysis. A small amount of sodium sulfide reduced the precipitation percentage of tellurium from 11.9% to 7.5% in an alkaline solution, and the direct recovery percentage of tellurium in the form of TeO2 exceeded 90%, while the purity of TeO2 reached 99.9%. By adjusting the pH of the bismuth solution to 0.15, 98.9% of the bismuth was able to precipitate and be recovered as BiOCl, with the purity also reaching 99.9%. In summary, this study presents an efficient hydrometallurgical method for treating bismuth telluride waste and provides theoretical guidance for reagent dosage, demonstrating the significant potential for industrial applications.

Microbial mechanisms to transform the super-trace element tellurium: a systematic review and discussion of nanoparticulate phases

Tellurium is a super-trace metalloid on Earth. Owing to its excellent physical and chemical properties, it is used in industries such as metallurgy and manufacturing, particularly of semiconductors and - more recently - solar panels. As the global demand for tellurium rises, environmental issues surrounding tellurium have recently aroused concern due to its high toxicity. The amount of tellurium released to the environment is increasing, and microorganisms play an important role in the biogeochemical cycling of environmental tellurium. This review focuses on novel developments on tellurium transformations driven by microbes and includes the following sections: (1) history and applications of tellurium; (2) toxicity of tellurium; (3) microbial detoxification mechanisms against soluble tellurium anions including uptake, efflux and methods of reduction, and reduced ability to cope with oxidation stress or repair damaged DNA; and (4) the characteristics and applications of tellurium nanoparticles (TeNPs) produced by microbes. This review raises the awareness of microorganisms in tellurium biogeochemical cycling and the growing applications for microbial tellurium nanoparticles.