Environmental Science And Technology - Mphil Thesis

Permanent URI for this collectionhttps://kr.cup.edu.in/handle/32116/86

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Adsorption studies for the removal of hexavalent chromium using fly ash of waste to energy power plant
(Central University of Punjab, 2013) Vaid, Upma; Mittal, Sunil
Chromium is the most common pollutant discharged in industrial effluent and reported to be present beyond permissible limits causing various health problems like carcinogenicity. Therefore, it must be removed from industrial effluent before its discharge. Several physico-chemical methods have been used for the removal of Cr (VI) from industrial effluents. Adsorption using activated carbon is quite efficient for the removal of Cr (VI) from industrial effluents. However, it is a costly process and the regeneration of activated carbon is difficult. Hence, in the present work, efforts have been made to explore the use of fly ash collected from the ‘Waste to Energy Power Plant’ as a low cost adsorbent. In order to maximize the Cr (VI) removal from simulated aqueous solutions, effects of various parameters (adsorbent dose, contact time, pH and initial metal ion concentration) on Cr (VI) adsorption were investigated by batch adsorption experiments. By optimizing the conditions for Cr (VI) adsorption using the fly ash, removal of hexavalent chromium from the aqueous solution (10 μg Cr/ml) was increased from 4% to approx. 99%. This shows that fly ash of agricultural waste burning can be used as an adsorbent for the removal of Cr (VI) at low concentration.
Removal of hexavalent chromium from aqueous solution using cone biomass of picea smithana as adsorbent
(Central University of Punjab, 2013) Najar, Gh Nabi; Mittal, Sunil
Chromium has wide range of uses in various metal and chemical industries. Hence, it is discharged in environment in large quantities with effluent from these industries. Cr(VI) compounds have been recognized as toxic and may cause skin irritation to lung cancer, liver, kidney and gastric damage. Various physical and chemical processes such as ion exchange, chemical precipitation, membrane process and electrolytic extraction are used for the removal of chromium (VI) from wastewaters. However, high cost, large input of chemicals and incomplete removal of metal ions are some major disadvantages with these methods. Therefore, adsorption seems to be a better process for the removal of metal ions including Cr(VI) from contaminated wastewaters because of the expediency, ease of operation and design simplicity. In the present work the batch adsorption study has been carried out on cone biomass of Picea smithiana (CBP) as low cost adsorbent for the removal of Cr(VI) from the aqueous solution in comparison to the most widely used adsorbent activated charcoal (AC). The cones of P. smithiana are the waste materials and are often used for burning. Effects of various parameters (adsorbent dose, contact time, pH and initial metal ion concentration) on Cr(VI) adsorption were studied by batch adsorption experiments in order to maximize the Cr(VI) removal from simulated aqueous solutions. Maximum Cr(VI) removal achieved from the aqueous solution (500 ?g Cr/mL) at pH 1, contact time 2 hours, adsorbent dose 1 g/L, and 25 + 2oC temperature using CBP and AC was 234.9 mg/g and 268.7 mg/g respectively. The present work indicates nearly 88% efficiency of CBP in comparison to the AC. This shows that CBP can be used as an efficient adsorbent for the removal of Cr (VI). The batch adsorption data of both CBP and AC was well fitted in Langmuir Isotherm model.