An increase in industrial, agricultural practices and several anthropogenic activities adds a significant amount of heavy metals in soil and water. Presence of these metals beyond the threshold limit is toxic for the flora and fauna of the surroundings. So, there is a need for removing the harmful heavy metals from the environment. Conventional methods such as precipitation, evaporation, electroplating, ion exchange, membrane processes, etc. have been ineffective because of technical and economic issues. Biosorption is a potential bioremediation technique that can be used for the removal of pollutants from aqueous medium and soil by the help of biosorbents (algae, fungi, bacteria, plants etc.). For increasing the biosorption capacity of biosorbents, they can be modified physically, chemically and genetically. Various factors affect the biosorption activity such as initial pH, temperature, bacterial activities and kinetics. This study describes the bacterial adsorbents, their modification and mechanism for removal of copper. A brief description of Langmuir and Freundlich isotherm modelling is provided in this paper.
Keywords: Bioremediation, biosorption, biosorbent, bacteria, heavy metals, copper.
Introduction
The intensive development of industry, agricultural practices and modern technologies are leading to the release of significant amount of contaminants to the environment (Ayres, 1992). Metals are inorganic form of contaminants whose extensive use has caused significant environmental pollution that mainly affects soil, watercourses, atmosphere and living systems (Kasassi et al., 2008). Mercury, lead, cadmium and chromium (VI) are considered as toxic metals; whereas, copper, nickel, cobalt and zinc are not as toxic, but their e...
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...displaying synthetic phytochelatins. Biotechnol Bioeng.70:518–24.
Majare, M. and Bulow, L. (2001): Metal-binding proteins and peptides in bioremediation andphytoremediation of heavy metals. TIBTECH. 19:67–73.
Chen, S. and Wilson, D. B. (1997): Genetic engineering of bacteria and their potential for Hg2+bioremediation. Biodegradation. 8:97–103.
Veglio, F.and Beolchini, F. (1997): Removal of metals by biosorption: A review. Hydrometallurgy. 44: 301-316.
Volesky, B. (2001): Detoxification of metal-bearing effluents: biosorption for the next century. Hydrometallurgy. 59:203–16.
Hu, M. Z. C. and Reeves, M. (1997): Biosorption of uranium by Pseudomonas aeruginosastrain CSU immobilized in a novel matrix. Biotechnol Prog. 13:60–70.
Bai, R. S. and Abraham, T. E. (2003): Studies on chromium(VI) adsorption–desorption using immobilized fungal biomass. Biores Technol. 87:17–26.
The Method of Extracting Copper and Gold by Bacterial Leaching The methods of extracting gold and copper have significant differences and therefore require separate attention. Prior to leaching occurring, either a tailings pile must be built up upon a base of impermeable rock or a series of holes drilled into the ore, to provide access for the bacteriaα. [IMAGE] At process one the bacteria thiobacillus ferro-oxidans and thiobacillus thio-oxidans, naturally occurring bacteria that obtain the energy that they need to survive by oxidising Fe2+ and S2- ionsα, are added to the copper ore. The bacteria in the acidic leaching solution then convert the insoluble sulphide minerals into a solution containing Cu2+, Fe2+, Fe3+ and SO42- ions. The acidic solution provides the optimum pH for the bacteria to work at. Following the bacterial action, the solution is drained off of the impermeable rock or pumped out of the ground through the remaining holes and the remaining solution prepared for concentration and extraction of the Cu2+ ions.
What if there was a way to clean up radioactive waste spills? To clean it out of waters for safe consumption? For years and years people have seen the ways that bacteria can clean up oil spills and nuclear waste, and where baffled on how they did so. How did something so small, clean up a mess so big? Gemma Reguera and her team at Michigan State have solved the age long question. They have decided that bacteria do so by a hair like pili. The pili acts much like a conductive wire, by transferring electrons. Geobacter Sulfurreduncen is one of the many bacteria that do so. The energy conducted by the pili, in turn powers the bacteria. Geobacter, for short, is able to both isolate and, in a sense, kill off uranium in contaminated ground water. So my question is, how effective would it be to clean out mass amount of uranium? First I had to learn about Geobacter and the types of waste created.
Arsenic is the 20th most common element in the earth’s crust and can be found naturally in our environment. There is around 0.006 to 0.03 ppm or arsenic distributed in seawater, and 20 ppm of arsenic in soil (before pesticides). Every human will ingest about 0.5 to 1 mg of arsenic in a day from food and water, because arsenic is present in higher quantities in se...
Heavy metals are characteristic parts of the Earth's covering. They can't be debased or destroyed. To a little degree they enter our body by means of drinking water, food and air. As follow components, some substantial metals (e.g. copper, selenium, zinc) are crucial to look after the metabolism of the human body. At higher concentrations they can accelerate poisoning. Devastating poisoning of metals arise from drinking-water pollution (e.g. lead channels), high surrounding air fixations close to emission sources, or through food chain.
Case Study - Corporate Obstacles to Pollution Prevention. Overview This case focuses on corporate obstacles to pollution prevention. Pollution prevention can be complex, especially for large corporations. There are many different forms of pollution prevention, including emissions control devices and incremental changes in existing technology.
Exposure to Mercury (Hg), Copper (Cu) and Lead (Pb) can cause long term health issues. Although, some of the elements may are useful in a rapid growing society they still pose a threat to public health as well as the ecosystem that pertain to wildlife. This research paper was conducted to further explain how these three metals Mercury (Hg), Copper (Cu) and Lead (Pb) have caused public health problems amongst the population while still being used for the greater good of a rising economy.
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The formation of the biofilm depends on factors like the type of surface used, presence of polymeric molecules on the surface and cell-cell interactions. Wastewater is passed through the surfaces on which the biofilms are attached. The microorganisms in the biofilm utilize the organic matter present in the wastewater and subsequently, the biofilms grow. There are four predominant reactor types that utilize this technology. Trickling Filters (TFs), Rotating Biological Contactor (RBC) Systems, Constructed Wetlands and Membrane Bioreactors (MBRs) (Sehar & Naz, 2016).
1999, 71, 181-215. Minear, R., Amy, G.. Water Disinfection and Natural Organic Matter: History and Overview. ACS Symposium Series -. 1996, 649, 1-9. Richardson, S. Water Analysis: Emerging Containments and Current Issues. Journal of Analytical Chemistry. 2003, 75, 2831-2857.
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In our days, mining for resources is inevitable. The resources we need are valuable in everyday life. Such resources mined up are coal, copper, gold, silver, and sand. However, mining poses environmental risks that can degrade the quality of soil and water, which can end up effecting us humans if not taken care of and many of the damages are irreversible once they have occurred.
Human interventions in watersheds, lakes and river systems take many forms - deforestation, farming, irrigation, river damming and extractions from subterranean aquifers. Wetlands play a crucial role in the filtering of fresh water, including the removal of various chemicals and potentially toxic elements, such as heavy metal pollutants, as cadmium and lead. (WHO, 2005).
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