Comparative study on metal ions adsorption on a low cost carbonaceous adsorbent kinetic equilibrium and mechanistic studies

A carbonaceous adsorbent prepared from an indigenous waste and treated by acid was tested for its efficiency in removing metal ions of Fe [II], Co[II] and Ni[II]. The process parameters studied included agitation time, initial metal ion concentration, carbon dosage, pH, other ions and temperature. The kinetics of adsorption followed first order reaction equation and the rate was mainly controlled by intraparticle diffusion. Freundlich and Langmuir isotherm models were applied to the equilibrium data. The adsorption capacity obtained from the Langmuir isotherm plots was found around 28mg/g for all selected metal ions at an initial pH of 6. The temperature variation study showed that the metal ions adsorption is endothermic and spontaneous with increased randomness at the solid solution interface. Significant effect on adsorption was observed on varying pH of the metal ion solutions. The type I and II isotherms obtained, positive delta H[0] values, pH dependent results and desorption of metal ions in mineral acid suggests that the adsorption of metal ions on this type of adsorbent involves both chemisorption and physical adsorption mechanisms

Biochemical study of freshwater fish Catla catla with reference to mercury chloride

Toxic activity of mercury chloride was tested in vivo on fresh water fish Catla catla. Acute toxicity tests were conducted to measure the impact of toxicity on the fishes within a short period at the various concentrations of HgCl[2] [0.1, 0.5, 1, 1.5, 2, 2.5 and 3mg/L]. The protein and carbohydrate were estimated using Anthrone by standard methods and enzymes such as Na[+]-K[+], Mg[2+] and Ca[2+] adenoxide triphosphatases were determined caloriemetrically. Depletion of protein was observed at all exposure periods. The biochemical estimation values of carbohydrates in muscle, intestine and brain showed significant values with P<0.05. The activity of Mg [2+] adenoxide triphosphatases in muscle, intestine and brain was studied and the maximum depletion was observed at 96h, 72h and 72h, respectively. Regarding activity of Ca [2+] adenoxide triphosphatases in muscle, the maximum depletion of this enzyme activity in muscle was observed at all exposure periods, except 96h. In intestine, enzyme activity was gradually decreased in all exposure and an increase was found during 96h. In brain, the enzyme activity was observed at all exposure periods except 96h