In the process of steel manufacture, up to ten millions of tons of sintering dust (SD) are produced annually in China, which contain noble metals such as Ag. Therefore, recovery of silver (Ag) from SD could be a potential economic and environmental activity. The purpose of this article is to generate information about reaction kinetics of silver leaching with thiourea from SD, comparing the conventional and ultrasonic-augment leaching. The effects of various control parameters such as the ultrasound power, particle size, leaching temperature and thiourea concentration on leaching rate of silver were studied. The results showed 89% silver recovery for conventional process against 95% for ultrasound assisted leaching. The ultrasonic wave increased the leaching rate and shorten the reaction time. The rate controlling step was analyzed using shrinking core model and the rate controlling step is identified to be the diffusion through the product layer in both conventional and ultrasonic-augment leaching processes. The activation energies were estimated to be 28.01kJ/mol and 18.19kJ/mol, and the reaction order were 0.89 and 0.71, respectively.
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http://dx.doi.org/10.1016/j.ultsonch.2016.05.038 | DOI Listing |
Environ Sci Pollut Res Int
January 2025
Department of Agricultural Chemistry, National Taiwan University, Taipei, 106319, Taiwan.
Rare earth elements (REEs) are emerging contaminants rendering potential risks in soils to environmental quality and human health. The causation between their geochemical signatures and contamination levels with parent rocks and soil properties are critical for REEs risk assessments, which are urgently needed globally. Thus, this study aimed to elucidate cause-and-effect among hydrofluoric-acid-digested total and ethylenediaminetetraacetic acid extracted bioavailable soil REEs and their contamination degree evaluated by pollution indices in 268 soil layer (horizon) samples from 50 soil profiles derived from felsic, intermediate, mafic, ultramafic, and sedimentary rocks in Taiwan.
View Article and Find Full Text PDFInt J Biol Macromol
January 2025
Department of Chemistry, Suleyman Demirel University, Faculty of Arts and Science, 32260 Isparta, Turkey.
Poly(lactic) (PLA) is a biodegradable material obtained from renewable resources and is recognized as a safe biopolymer by the Food and Drug Administration. PLA expresses excellent mechanical and moldability attributes nonetheless poor elasticity/functionality limits its widespread utilization. One approach to compensate for this is chemical surface modification through free radical grafting with small organic molecules like maleic anhydride (MA).
View Article and Find Full Text PDFSci Total Environ
January 2025
Global Centre for Environmental Remediation (GCER), College of Engineering, Science and Environment, University of Newcastle, University Drive, Callaghan, NSW 2308, Australia; crc for Contamination Assessment and Remediation of the Environment (crcCARE), ATC Building, University Drive, Callaghan, NSW 2308, Australia. Electronic address:
Agricultural activities are essential for sustaining the global population, yet they exert considerable pressure on the environment. A major challenge we face today is agricultural pollution, much of which is diffuse in nature, lacking a clear point of origin for chemical discharge. Modern agricultural practices, which often depend on substantial applications of fertilizers, pesticides, and irrigation water, are key contributors to this form of pollution.
View Article and Find Full Text PDFEnviron Manage
January 2025
Department of Engineering, Reykjavik University, Reykjavík, Iceland.
This research assesses heavy metal contamination within the riparian zone of the Danro River, a tributary of the Ganges River basin in India, particularly impacted by sand mining activities. The study conducted analyses on major and trace elements in soil samples, focusing on those identified as ecologically hazardous by the Water Framework Directive of India. Utilizing a combination of indices (Enrichment Factor, Pollution Load Index, and Index of geo-accumulation) and statistical techniques such as Principal Component Analysis (PCA), the investigation aimed to evaluate contamination severity, ecological risks, and pollution sources.
View Article and Find Full Text PDFACS Appl Mater Interfaces
January 2025
Instituto de Química, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-909, Brazil.
COVID-19 disease, triggered by SARS-CoV-2 virus infection, has led to more than 7.0 million deaths worldwide, with a significant fraction of recovered infected people reporting postviral symptoms. Smart surfaces functionalized with nanoparticles are a powerful tool to inactivate the virus and prevent the further spreading of the disease.
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