In present study, the maximum uptake of Pb (II) ions was at optimum pH 6.0 (Fig. 4.1). The efficiency of sorption of Pb (II) increased with the increase in pH value because at higher pH, more ligands were available for Pb (II) ions binding whereas at lower pH, there was competition for active binding sites between protons and metal ions. At low pH, the amount of H + ions was high so Pb (II) ions had to compete with H + to get attached with surface functional groups of shell biomass. On the other hand, at high pH, due to decreased no. of H + in the solution, Pb (II) ions may have enhanced probability to bind with free binding sites. However, in alkaline pH, Pb (II) may tend to precipitate in solution, thus decreasing the quantity of soluble sorbent available for sorption.”
. The highest percentage of Leadremoval in acidic conditions may be due to an increase in the maximum amount of dissolved hydroxyl ions in water in this situation. The hydroxyl radical is formed in this case . Therefore, pH=5 is determined as the optimal pH in this test. In Fenton reaction, hydroxyl radical acts as the chief oxidizing agent. On the other hand, the lowest removal percentage may be due to the low exchange between Pb and OH. It should be noted that the low pH results in the production of a right amount of hydroxyl radical. Besides, the lower removal percentage in higher pH may be due to the formation of Ferrous and Ferric hydroxyls which reduce the production of hydroxyl radical in a reaction . Meijuan et al. obtained the similar results in this regard .
There were initial increases in removal efficiency with corresponding increase from day 1 to 9. These findings showed a great disparity with Stylianou et al., , which reported that using synthetic inorganic chelating agents, maximum heavymetalremoval efficiency is attained in less than 24 hours. It is worthy to know that the initial faster rate was due to the availability of the uncovered surface area of the extractants since the kinetics depends on the surface area of the extractants. The extraction takes place at the more active binding sites and as these sites are progressively filled, the
Today, heavymetal contamination is a major environmental concern across the world. Some of the common heavymetal pollutants in industrial wastewater include lead, copper, cadmium, and nickel. This study aimed to compare the efficiency of duckweed in the removal of heavy metals from aqueous solutions in combined and separate forms. This applied, fundamental research was conducted based on empirical studies. Heavymetal solutions were prepared at the concentrations of 5, 10, and 25 mg/l, and duckweed (weight: 0.2, 0.4, 0.8, and 1.2 g) was added to the prepared solutions (100 ml). Plant weight in the combined solution was four times higher than the separate solution. After the contact time of five, 10, and 15 days, heavymetal residues in the solutions was measured using ICP-OES. According to the results, heavymetalremoval from the separate solutions differed with the combined solutions. Both systems were compared in terms of the contact time, initial heavymetal concentration, and removal order. The obtained results indicated that the removal efficiency of heavy metals was higher in the combined solutions compared to the separate solutions. Increased initial concentration also reduced removal efficiency in the separate solutions, while the removal rate remained constant in the combined solutions. Moreover, the heavy metals in the combined solutions were removed within a shorter time. The removal sequence of the heavy metals from separate solutions was lead>cadmium>nickel>chromium at the maximum removal time. In the combined heavymetal solutions, such removal rate sequence was not observed.
attachment (Chen, Chen and Yue 2000). For restaurant wastewater treatment, EC process efficiency was studied by Chen et al. The authors found that the bubbles formed by EC were not sufficient for a high removal efficiency of suspended solids. The reasons were primarily related to the reactor configuration, which promoted the formation of large hydrogen, this, in turn, disturbed the flow and decreased the contact between particles and bubbles. Another reason that affects bubble size and generation is that the electrode surface, due to the passivation, has a rough surface, which provides larger adhering forces to bubbles than smooth surfaces, thus decreasing their generation (Chen, Chen and Yue 2000).
ABSTRACT: Environmental pollution particularly from heavy metals and minerals in the wastewater is the most serious problem in India. Due to extensive anthropogenic activities such as industrial operations particularly mining, agricultural processes and disposal of industrial waste materials; their concentration has increased to dangerous levels. Heavy metals in industrial effluent include nickel, chromium, lead, arsenic and cadmium. So far, a number of efficient methods have been reviewed for the removal of heavy metals such as chemical precipitation, ion exchange, reverse osmosis, electro-dialysis, ultra-filtration, nano-filtration, coagulation, flocculation, floatation, etc. However, these methods have several disadvantages such as high reagent requirement, unpredictable metal ion removal, generation of toxic sludge etc. Adsorption process being very simple, economical, effective and versatile has become the most preferred methods for removal of toxic contaminants from wastewater. This paper reviews the use of various readily available natural materials as adsorbents of heavy metals from industrial wastewater. Various adsorbents reviewed include activated carbon, activated alumina, iron acetate activated alumina, silica gel, hydrogels, magnetic graphene oxide. And also Various low cost adsorbents reviewed includes sand, used tea leaves, eggshell, rice husk, activated carbon, olive stones, wood sawdust etc.
pH- 5; Time-60min; Uptake-99.05mg/g pH- 5; Time-60min; Uptake-68.92mg/g The table shows that various type of fruit biosorbent had been used to different kind of target heavy metals. Each fruit biosorbent need different condition of pH, contact time and yield different metal uptake. The results also show that fruits are a promising biosorbent. As stated in the earliest discussion the cell wall of fruit waste containing polysaccharides help to absorb target heavy metals. In Malaysia, diverse industries discharge effluent containing a mixture of pollutant including heavy metals. Therefore, there is a great potential of using other locally fruit waste material as biosorbent in treating the wastewater containing heavy metals. Fruit waste materials are typically generated large quantities by the fruit juice industry or fruit stall locally. These materials have received little scientific attention, in spite of high quantity of pectin, which contain carboxyl group. The plant cell wall polysaccharide pectin consists mostly of polygalacturonic acid (carboxyl group). Normally, polysaccharide pectin is commercially extracted from sugar beat, apple and citrus peels. Due to similarity of pectin, such fruit materials namely banana, watermelon or honeydew are predicted as a very promising biosorbent. However their biosorption potential has only been studied to a limited extent in spite of their abundant availability at minimal cost.
Expansion of mining activities is one of the most important and destructive industrial process, that in the absence of management, will have considerable impact on the environment. This effects and consequences of irreparable, all living and non- living components of the ecosystem, such as water, soil and air are overshadowed. Generally, damage to land and soil and water resources by mining, mainly depends on the conditions of topography and soil characteristics (Rodriguez et al, 2009). Soils exposed to mining operations are often chemically activated, and thus will be a source of water pollution. Mining be considered as one of the most important centers of pollution emissions, from the point of heavymetal compounds. In general, heavy metals because of unreliable data, and physiological effects on the ecosystem, in low concentrations as dangerous environmental pollutants are considered and high evaluated (Azarpour, 2012). Heavy metals have significant environmental pollutants, and their toxicity have environmental , evolutionary and nutrition reasons. Heavy metals '' refers to any metallic element that has a relatively high density and is toxic even in low concentrations (Lenntech, 2004). Heavy metals in a comprehensive term, including a group of metals and semi- metals by atomic density greater than 4 or 5 or more, in grams per cubic centimeter (Hernandez, 1996). Soils , are the source of metals. Metals in the soil , are concentrated in the top soil, threaten plants and vegetation. Some of these heavy metals like copper and zinc as a cofactor and activator of enzymatic reactions, for example, Information enzyme or are applying a catalytic features such as prosthetic groups. in some soils , rare-earth metals are in some oxidation and reduction reactions, electron transport, and structural functions in nucleic acid metabolism. Some heavy metals such as cadmium and mercury, as highly sensitive enzyme, also react to the metal. Thereby, cause growth inhibition and death organisms (Mildvan, 1970).
Aims and objectives: To study the views of Doctors on heavymetal poisoning in Mumbai Material and methods: Heavy metals, like arsenic, lead, mercury, and others, are all around us. They’re in the ground we walk on, in the water we drink, and in the products we use every day. But high levels of most heavy metals can make you sick. While our bodies need small amounts of some heavy metals — such as zinc, copper, chromium, iron, and manganese — toxic amounts are harmful. If our body's soft tissues accumulate too much of heavy metals, the resulting poisoning can cause serious damage. Though there is variety of medical uses of heavy metals, still each metal has its own side effects which disturb human health. We have to use solid evidence that demonstrates the safety, efficacy, and effectiveness of specific alternative medicine. Also We have to study General biocompatibility (how metals react with human tissue) and Immunological biocompatibility (The adverse reaction due to an immunological or allergic type response from metals). For the better study of heavymetal toxicity, we have carried out survey taking opinions of Doctors in Mumbai and Thane region.
Chitin and its deacetylated form, chitosan, are two biopolymers that come from crustacean shells and have the ability to fix a great variety of heavy metals.  The strong affinity of metal ions for these sorbents is explained by the relatively high proportion of nitrogen sites. The use of these biopolymers can be a low cost alternative for the removal of contaminants from industrial effluents and from the natural water supply. The metal sorption capacity of chitosan varies with crystalline, affinity for water, deacetylation degree and amino group content. Kinetic studies have demonstrated that the rate of metallic ion sorption onto chitosan differs depending on the raw material (shrimp, crab or lobster shells), preparation method, chemical modification, and chitosan particle shape. Wu evaluated the sorption capacities and rates for Cu(II) onto flakes and bead forms of chitosan prepared from fishery wastes.  Structure of chitosan is given below.
The presence of toxic xenobiotics in water bodies such as azo dyes , detergents , acrylamide [23-24], diesel [25-26], pesticides  and heavy metals [5,27,28,29] is a global phenomenon that have warranted the development of technologies to detect and remediate these xenobiotics. Of all the xenobiotics, heavy metals are so prevalent in various parts of the world that many researchers have begun to embark upon various methods to monitor toxic heavy metals . Heavy metals, unlike organic pollutants, cannot be detoxified via degradation and thus they persist in the ecosystem. Their toxic effects to aquatic organisms are well documented [10-12]. The infamous case of mercury poisoning in Minamata, Japan resulting in a massive outbreak of methylmercury poisoning represents a tragic example . The Department of Environment, Malaysia has revealed that states with high industrial development (Pulau Pinang, Johor and Perak) have high levels of heavymetal (lead and mercury) contamination. Copper was found highest in the waters of Kedah and Langkawi with 50% of sampling sites exceeding the Interim Standards . Thus, there is a need for simple and fast procedures as a preliminary screening method to determine the presence of toxic heavy metals.
World’s population is increasing steadily. The issues concerned with it like food security, water shortage problem are also increasing alarmingly. Due to socio-economic conditions in the third world countries, wastewater is used for agricultural purposes. Application of heavymetal contaminated wastewater, such as cadmium, copper, lead, iron and manganese etc., would pollute soil and water bodies. The heavy metals taken up by plants in the vicinity, directly or indirectly affect human and animal health . Heavymetal ions could be eliminated by several traditional techniques such as reverse osmosis, chemical precipitation, electrochemical treatment techniques, ion exchange, membrane filtration, coagulation, extraction, irradiation and adsorption. Adsorption technology would be most promising due to its low cost-effective, high efficiency, and simple to operate . The materials like activated carbons, chelating materials, clay minerals, and chitosan/natural zeolites have been adopted to adsorb metal ions from aqueous solutions. Although these traditional materials
A heavymetal is any relatively dense metal or metalloids that are noted for its potential toxicity especially in environmental contexts. Heavymetal poisoning has particular application to cadmium, mercury, lead and arsenic all of which appear in the WHO's list of 10 chemicals of major public concern. Heavy metals can bind to and interfere with the functioning of vital cellular components. Common
Conclusion: Bacterium isolated from a contaminated site showed the ability to remove a high amount of lead and copper. Thus, MKH3 could be useful for the bioremediation of heavy metals, particularly lead and copper, from industrial wastewater and contaminated sites.
A simple, rapid and low cost non-thermal method has been developed to synthesize cerium(III) incorporated mesoporous molecular sieves (with Si/Ce ratios of 10, 20, 40, and 80) with high thermal stability and high surface area and pore volumes. The distribution coefficients of the heavymetal ions on this sorbents show good selectivity of these materials for a number of ions in water. The prepared materials show high potential to be used as new promising adsorbent in removal of heavymetal ions from wastewaters.
In a German study from 2009, carried out by Bundesministerium für Ernährung, Landwirtschaft und Verbraucherschutz (carried out in the light of the implementation of the regulation in the field of tattooing in Germany that came into effect on 1 May 2009), the metal content and preservative content was investigated in 148 commercial tattoo inks. The samples showed a large content of copper, iron, chrome and zinc and a smaller amount of tin, lead, manganese, selenium, arsenic, thallium, mercury and uranium 38 . In another American study
Toxic heavy metals, which primarily originate from automobile-related activities and the exposure of building materials to rain, are among the most important pollut- ants associated with urban stormwater runoff . Cop- per, lead, cadmium, and zinc are by far the most com- mon priority pollutant elements. some of the metals are present often enough, and in high enough concentrations, to be potential threats to the beneficial use of most water resources . stormwater filters can be used as the effec- tive heavymetalremoval method in cases where metal ions, and small particles containing heavy metals, are not
Transport of the metal across the cell membrane yields intracellular accumulation, which is dependent on the cell's metabolism. This means that this kind of accumulation may take place only with viable cells. It is often associated with an active defense system of the microorganism, which reacts in the presence of toxic metal. During non-metabolism dependent process metal uptake is by physico- chemical interaction between the metal and the functional groups present on the microbial cell surface. This is based on physical adsorption, ion exchange and chemical sorption, which is not dependent on the cells' metabolism. Cell walls of microbial biomass, mainly composed of polysaccharides, proteins and lipids have abundant metal binding groups such as carboxyl, sulphate, phosphate and amino groups. This process i.e., non- metabolism dependent is relatively rapid and can be reversible. In the case of precipitation, the metal uptake may take place both in the solution and on the cell surface .Further, it may be dependent on the cell's' metabolism if, in the presence of toxic metals, the microorganism produces compounds that favor the precipitation process. Precipitation may not be dependent on the cells' metabolism, if it occurs after a chemical interaction between the metal and cell surface.
prepared contaminated soil had the advantage of good homogeneity in terms of consistent heavymetal concen- tration and speciation, soil composition, contamination process, and contamination period. This would minimize ambiguity in the extraction results arising from sample heterogeneity. To minimize the discrepancy between the field-contaminated soil and the artificial-contaminated soil, the soil samples were equilibrated for 2 weekss in wet condition followed by dry aging for more than 4 weeks. The wet aging stage was essential to ensure com- plete and even exposure of every soil particle to con- tamination. At the end of the 2-week wet-aging period, the soils were separated from solution, dried and aged further for another 4 weeks before soil characterization and extraction experiment were carried out.