Introduction
Nowadays, industrial activity in the world has grown very fast. In addition to induces positive impacts, the growth of industry also generates a new problem for the environment and so we need to search an effective and efficient handling ways of negative impacts such as waste. One example of pollutions due to industrial wastes is a pollution caused by waste containing in dissolved heavy metals. Waste with a high content of heavy metals could be dangerous pollutants. One of heavy metals that are harmful is chromium. Chromium contained in waste usually has a valence of three (Cr3+) and valence of six (Cr6+). Heavy metals such as chromium waste derived from metal plating industry (electroplating), paints/pigments industry and leather tanning industries. Cr waste (VI) is concerned because of its carcinogenic properties. Interestingly, only Cr(VI) which are carcinogenic, while Cr (III) is not (Mariana, et al, 2006). The toxicity level of Cr (III) is only about 1/100 times that of Cr (VI). Some of handling methods of Cr (VI) waste has been conducted through chemical reduction and ion exchange (Slamet et al. 2003).
In general, the methods used for handling of Cr (VI) waste require high cost and long process. There are other alternatives for removal of chromium from industrial waste by adsorption method using biomaterials. This method is a very promising method for treating industrial waste, mainly because it is cheap and has a high absorption capacity. Some examples of research that has been done by using biomaterials as bio-sorbent to absorb Cr (III) by using seaweed (Sudiarta, 2009), the utilization of peanut shell as a bio-sorbent for reactive dye of Cibacron Red (Aprilia S, 2009), absorption of copper ions using chitosa...
... middle of paper ...
... mg/L.
Figure 3 shows the relationship of temperature to absorption capacity of Cr (VI). At temperatures of 35 ºC and 50 ºC, the contact time of 120 minutes and concentration of 50 mg/L, absorption capacity was obtained as much as 1.5256 and 1.6752 mg/g, respectively. Based on these data it can be seen that the higher of applied temperature then the greater of absorption capacity. This is probably due to the empty pores exist in the adsorbent will get bigger. Therefore if it is used to absorb the adsorbate at the same temperature then absorption capacity become greater.
Conclusions
The optimum absorption process of Cr6+ metal with adsorbent dose of 1 g and contact time of 60 minutes was obtained at concentration of 50 mg/L and temperature of 50º C. The best absorption process of Cr (VI) metal ions using guava leaves was obtained on contact time for 30 minutes.
Neidig, H. A., and J. N. Spencer. "Precipitating Lead Chromate on a Small Scale." General Chemistry For Engineering And Science. Mason: Cengage Learning, 2012. 83-90. Print. Signature Lab Ser.
In the first part of this project, two cation elimination tests and one cation confirmation test were performed. 10 drops of 4 cation solutions: potassium, zinc(II), copper(II)
Many industries like papers, textiles, gasoline, and leather are huge users of azo dyes which contains the largest group of substitute organic chemicals. The waste produced from these industries and resulting by-products have both metal ions and dyes. These waste products become hazardous when present in the surroundings. The insolvable dyes have low decomposability and only 45–47% dyes materials are known as biodegradable (Rauf and Ashraf., 2012)...
The molar absorption coefficient can be found in an absorption spectrum. The absorption spectra is generate...
The surface morphological changes of powder and carbon samples were investigated using a Scanning Electron Microscope (SEM). The figure 2 and 3 shows the Scanning Electron Microscopy of orange peel powder and carbon made from powder. Carbon made from powder showed more porous structure than orange peel powder. Orange peel powder showed vertical vein type structure and carbon made from powder showed more porous structure with holes which gave maximum adsorption capacity than the orange peel powder.
Numerous works (Abreu &Campana-Filho, 2009; An, Dung, Thien, Dong, &Nhi, 2008; Anitha et al., 2009; Ge&Luo, 2005; Hjerde, Varum, Grasdalen, Tokura, &Smidsrod, 1997; Kittur, Harish Prashanth, UdayaSankar, &Tharanathan, 2002; Mourya, Inamdar, &Tiwari, 2010; Muzzarelli, Tanfani, &Emanuelli, 1984; Rinaudo, Dung, Gey, &Milas, 1992; Xu, Xin, Li, Huang, & Zhou, 2010) have been carried out on CM-chitosan. Du &Hsieh(2008) showed that longer alkalization and ca...
Physical adsorption takes place when the Vanderwaals forces bind the adsorbing molecule onto the solid substrate; those intermolecular forces are similar to the bond molecules to the surfaces of a liquid. The heats of adsorption are comparable in magnitude to latent heats (10 to 70 KJ/mol). Specifics that are physically adsorbed to a solid may be released through making use of heat; the process is reversible. An increase in temperature causes a lower in adsorption efficiency and capacity. Chemical adsorption occurs when covalent or ionic bonds are formed among the adsorbing molecules and the solid substrate. This bonding results in a change within the chemical form of the adsorbed compounds, and is therefore not reversible. The bonding forces for chemical adsorption are much more than for physical adsorption. Therefore, extra heat is liberated. With chemical adsorption, higher temperatures can improve the overall performance
This experiments were carried out to investigate the potential of banana peel as adsorbent for the removal of heavy metal. For this experiment, the bisorbent is untreated and less remove of heavy metal than treated biosorbent.
In the present techno-economic era, the energy and environmental crises developed due to huge amount of cellulosic materials disposed as “waste”. Globally, the estimated quantity of the waste generation was 12 billion tons in a year 2002 of which 11 billion tons were industrial wastes and 1.6 billion tons were municipal solid waste. About 90 billion tons solid wastes will expected to be generated annually by the year 2025. Annually, Asia alone generates 4.4 billion tons of solid wastes and municipal solid waste comprises 790 million tons of which about 48 million tons are generated in India.
In attempts to restoring safe levels of drinking water in Bangladesh, continuous research and scientific analysis are being implemented. A number of new technologies, as well as common strategies have been set in motion to alleviating arsenic in the countries groundwater. A number of these methods include: oxidation, co-precipitation, sorption, filtration, ion exchange as well as promising results from a range of adsorption based technologies.
The industrial waste water consists of process wastes, cooling water and sanitary waste the process of segregation of cooling waste from the remaining portion will greatly reduced the load on the treatment plant. The segregation produces two types of wastes. One waste is very strong but less in volume and the second waste is weak and more or less same as the original volume. This makes the treatment process easier and reduces the difficulty of treating the total volume of waste generated. The strong waste which is low in volume can be treated specifically by selecting a suitable treatment method based on physic chemical characteristics of the strong waste.
Phytoextraction is the uptake and storage of pollutants in the plants stem or leaves. Some plants, called hyperaccumulators, draw pollutants through the roots. After the pollutants accumulate in the stem and leaves the plants are harvested. Then plants can be either burned or sold. Even if the plants cannot be used, incineration and disposal of the plants is still cheaper than traditional remediation methods. As a comparison, it is estimated a site containing 5000 tons of contaminated soil will produce only 20-30 tons of ash (Black, 1995). This method is particularly useful when remediating metals. Some metals are also being recycled from the ash.
...croorganisms present in wastewater as the anodic solution obtained from different sources made me to understand that microbes present in domestic as well as industrial waste can even be proved beneficial if they are tapped for electricity generation. Such results were based on the preliminary experiments which need further research in the field . I did it on laboratory level and at the end could generate enough electrical energy to light a bulb or to run a calculator for a few hours to a day.
The adsorption studies were performed in batch experiments by agitating definite amounts of the studied resin with Hg2+ aqueous solution with predetermined concentrations at varying pH values, temperatures and for deferent time intervals. For pH studies; 0.05g of the studied resin was equilibrated with 50mL 100mg/L Hg2+ solution for 3h at 300C. HCl/KCl was utilized to adjust the pH range 1-3, CH3COOH/CH3COONa was used for pH 4 and 5. For temperature effect studies, 0.05g of the resin were equilibrated with 50mL Hg2+ aqueous solution with initial concentration 50mg/L and pH 5 for 3h at 150rpm in temperature range 20-40. The kinetic studies were carried out by shacking 0.5g of the
It also decreases the amount of sludge, which needs to be disposed. Electrocoagulation is a technology that removes components from wastewater by applying a strong electric field that produces a series of oxidation and reduction reactions. By decomposing the electrodes, the metallic ions produced are subject to fast hydrolysis and the products of the hydrolysis neutralize the charge of the suspended particles driving them to a fast coagulation and sedimentation. Electrodes consist of iron and aluminium have special coagulation properties and are very efficient in decolouring industrial wastewater. In recent years, the EC has been successfully tested to decolourization of dye-containing solutions. Applied electrodes in EC process are usually iron or aluminium. The dye in coloured wastewater is coagulated by iron and aluminium hydrates or hydroxides produced from the sacrificial anode. EC technology, compared with other techniques, enjoys some advantages like plain equipment, easy functionality, short resistance time, no need of chemicals, low sludge production, sludge stability, suitable sedimentation of sludge, dewatering and environmental compatibility. EC process is being used for the removal of ions, organic matters, colloidal and suspended particles, dyes, oil and heavy metals from aqueous