title: Adsorptive separation of cadmium from aqueous solutions and wastewaters by riverbed sand.
abstract: Application of riverbed sand for the adsorptive separation of cadmium(II) from aqueous solutions has been investigated. Removal increased from 26.8 to 56.4% by decreasing the initial concentration of cadmium from 7.5 x 10(-5) to 1.0 x 10(-5)M at pH 6.5, 25 degrees C temperature, agitation speed of 100 rpm, 100 microm particle size and 1.0 x 10(-2) NaClO4 ionic strength. Process of separation is governed by first order rate kinetics. The value of rate constant of adsorption, k(ad), was found to be 2.30 x 10(-2)per min at 25 degrees C. Values of coefficient of mass transfer, beta L, were calculated and its value at 25 degrees C was found to be 1.92 x 10(-2)cm/s. Values of Langmuir constant were calculated. Values of thermodynamic parameters delta G0, delta H0 and delta S0 were also calculated and were recorded as -0.81 kcal/mol, -9.31 kcal/mol and -28.10 cal/mol at 25 degrees C. pH has been found to affect the removal of cadmium significantly and maximum removal, 58.4%, has been found at pH 8.5. Process can be used for treatment of cadmium(II) rich wastewaters.
authors: Environmental Engineering and Research Laboratories, Department of Applied Chemistry, Institute of Technology, Banaras Hindu University, Varanasi 221 005, India. y_sharma_2002@rediffmail.com
authors: Y C
authors: YC
authors: Sharma
authors: S N
authors: SN
authors: Kaul
authors: C H
authors: CH
authors: Weng
mesh_terms: D000327:Adsorption; D002104:Cadmium; D052918:Environmental Restoration and Remediation / Q000379:methods*; D006863:Hydrogen-Ion Concentration; D009994:Osmolar Concentration; D010316:Particle Size; D045483:Rivers; D012822:Silicon Dioxide; D013696:Temperature; D014865:Waste Disposal, Fluid; D014874:Water Pollutants, Chemical
chemical_list: D014874:Water Pollutants, Chemical; D002104:Cadmium; D012822:Silicon Dioxide