Comparative study on the removal of copper (II) and nickel (II) from aqueous soluion using cellulose extracted from sisal fiber and cellulose grafted acrylonitrile copolymer

Hajeeth, T Gomathi, & Sudha
2014 Indian Journal of Chemical Technology   unpublished
Batch adsorption studies have been carried out to remove Cu (II) and Ni (II) ion from aqueous solution using cellulose extracted from sisal fiber and cellulose-g-acrylonitrile copolymer by steam explosion method. The effect of pH, contact time and amount of adsorbent dose have also been investigated for both cellulose extracted from sisal fiber and cellulose-g-acrylonitrile copolymer. From the observed results, it is evident that the adsorption of metal ions increases with the increase in
more » ... e increase in contact time and adsorbent dosage. The optimum pH is found to be 5.0 for the removal of copper (II) and nickel (II) for both the extracted cellulose and cellulose-g-acrylonitrile copolymer. The adsorption kinetics of cellulose and cellulose-g-acrylonitrile is found to follow pseudo-second-order kinetic model. The experimental data are fitted to Langmuir adsorption isotherms for both cellulose extracted from sisal fiber and cellulose-g-acrylonitrile copolymer. From the results it is concluded that the cellulose graft acrylonitrile copolymer is found to be efficient adsorbent for the removal of heavy metals from aqeous solutions. Water is one of the essential items needed for living beings for the survival and growth. It also maintains an ecological balance between various groups of organisms and their environment. The quality of water is of initial concern for mankind since it is directly linked with human welfare 1. Heavy metals are widely used in the industries like textiles, leather, paper, plastics, electroplating, cement, metal processing, wood preservatives, paints, pigments and steel fabricating industries 2. These industries discharge large quantities of toxic wastes and the untreated effluents from these industries causes water pollution 3. Heavy metals are classified into the following three categories: toxic metals (Hg, Cr, Pb, Zn, Cu, Ni, Cd, As, Co, Sn, etc.), precious metals (Pd, Pt, Ag, Au, Ru, etc.) and radionuclides (Ra, Am, etc.) 4. The presence of heavy metal in environment is of major concern because of their transformation from relatively low toxic species into more toxic ones. Some metal ions such as Hg and Cd are highly toxic even in lower concentration 0.001-0.1 mg/L (Ref. 5). The current physicochemical processes for heavy metal removal like (precipitation, electrochemical treatment, ionexchange, adsorption on activated carbon) 6 etc. are expensive and inefficient in treating large quantities. They also cause metal bearing sludges which are difficult to dispose of. More stringent rules by the government and media and public pressure regarding effluent discharges have necessitated the search for newer methods of treatment 7,8. The excessive levels of heavy metals have been linked with a wide range of health conditions, including skin disease, birth defects and cancer 9 and so the World Health Organization has recommended strict controls on the percentages of various heavy metals in effluent waters. Since the cost of these materials is much lower than the cost of commercial adsorbents, such as activated carbon or ion-exchange resins, the prepared biological materials might gain a special attention. These materials including: activated carbon 10-13 , lignite 14 , kaolinite and ballclay 15 , diatomite 16 , coconut fiber 17 sisal fiber and limestone 18. Cellulose fibres are becoming popular because they are cheap, renewable and low in density, and exhibit better processing flexibility 19. Among many natural fibers, sisal is of particular interest due to its moderate high specific strength and stiffness,