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My research interests are bioremediation of polluted environments and biotreatment of solid wastes.
During my master's, I allocated most of my studies to metal recovery from e-wastes, and industrial wastes by biohydrometallurgy.
In my master project, extracting and leaching of heavy metals from electroplating sludge by Bioleaching process was studied. The high content of toxic heavy metals such as chromium, zinc, copper, nickel, and cadmium makes electroplating sludge a potential threat to the environment. Also, because of the massive production of electroplating sludge in the order of many hundred thousand tons at the world level, this waste is considered as a valuable secondary resource that must be recovered. In this research, we have used biogenic organic acids which are produced by fungi as the most critical lixiviants for leaching of heavy metals, because biogenic organic acids are more eco-friendly in comparison to inorganic acids and chemical organic acid.
In the following read more about my works and publications:
Abstract
Electroplating sludge is classified by environmental agencies as a hazardous waste, the disposal of which can be a serious environmental concern. In the present study, the recovery of Ni and Cr from chromium-rich electroplating sludge was conducted using the filtrated culture of Aspergillus niger for the first time. Pulp density, leaching temperature, and leaching duration were identified as variables affecting the recovery optimization. Leaching temperature of 66 °C, leaching duration of 1 day, and pulp density of 10 g/L were found as the optimal conditions. Under optimum conditions, Cr and Ni recoveries were 53% and 95.7%, respectively. Toxicity Characteristic Leaching Procedure and Synthetic Precipitation Leaching Procedure tests showed that electroplating sludge was effectively detoxified by bioleaching. The kinetic studies demonstrated that the leaching proceeded with one stage kinetics for Cr and two stages kinetics for Ni. Cr recovery was controlled by interface transfer and diffusion across the product layer. Also, the first stage of Ni leaching was controlled by interface transfer and diffusion across the product layer, and the second stage of Ni leaching was a mixed-control mechanism and both diffusion through the product layer and chemical reaction were involved. Eventually, the results of this study represent the filtrated culture of Aspergillus niger has the ability to recover metals from electroplating sludge and detoxify it. Abstract
Graphical abstract
Graphical abstract
Abstract
Abstract
The management of industrial wastes is an important aspect of environmental engineering that not paying attention to it can cause so many problems including loss of valuable metals, pollution of the environment and human health risks. Among them, plating residue (PR) is classified as hazardous waste. Biological leaching is an efficient method of recovering metals from PR and can decrease heavy metal toxicity. In this research, at first, the optimal culture medium among four culture mediums (Czapek Dox Broth, Czapek Dox Broth-modified, Bosshard and Malt extract) was investigated. Finally, Bosshard was chosen as appropriate culture medium for leaching of PR. In the next stage, Bioleaching of Ni, Cr, and Cu from PR was conducted in different pulp density of 5, 10, 20 and 40 g/L. Eventually, the highest recovery of heavy metals (Ni: 186000 mg/kg, Cr: 45000 mg/kg and Cu: 12000 mg/kg) happens in the pulp density of 5 g/L.
Abstract
Abstract
Along with the development and industrialization of societies, the demand for heavy metals is on the rise, while the rich mineral ores of these metals have declined. Today, other sources of metals with higher grade, such as spent catalysts, fly ashes, electroplating sludge and most importantly, electrical and electronic wastes have been taken into consideration. Recovery of heavy metals from these secondary sources by conventional methods such as pyrometallurgy and hydrometallurgy has some disadvantages including high energy consumption and high utilization costs, the risk of environmental pollution, and public health threats. Due to the strict environmental regulations, especially in the field of toxic waste disposal and also with the cost of applying these rules, there is a need for new, environmentally friendly and more effective technology for recycling wastes. In this discussion, the methods of electrical and electronic waste recycling, which include pyrometallurgy, hydrometallurgy, and biohydrometallurgy have been studied. Among them, bioleaching has been introduced as an effective, inexpensive and consistent with the environment.
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