University of Tehran Press Iranian Journal of Soil and Water Research 2008-479X 46 1 2015 03 21 Influence of pH and Ionic Strength on Cadmium Sorption by Some Biosorbents Influence of pH and Ionic Strength on Cadmium Sorption by Some Biosorbents 133 140 54302 10.22059/ijswr.2015.54302 FA Ebrahim Sepehr Assistant Professor, Faculty of Agriculture, University of Urmia Amir Tosan Former Graduate Student, Faculty of Agriculture, University of Urmia Journal Article 2013 10 27 To study the effect of pH and ionic strength on the sorption behavior of cadmium by biosorbents, a batch experiment was conducted with various initial concentrations of Cd2+ (0 – 200 mg.L-1) with two biosorbents (sunflower stalks and apple pruning residues) in two pH (4, 8) levels and two ionic strengths (0.1 and 0.03 M). Sorption data were fitted to Langmuir, Temkin and Freundlich Equations. Results showed that both pH and ionic strength (IS) had significantly affected Cd sorption. Langmuir maximum mono layer adsorption (qmax) and binding energy value (KL) increased with increasing pH by two biosorbents. Sorption coefficients of Freundlich (KF, n) and Temkin (KT , A) indicated similar trends as well. But by increase in IS (from 0.03 to 0.1 M) all the sorption parameters decreased significantly. As for the case of sunflower stalks; with increase in ionic strength, qmax on the average, decreased from 8505 to 8150 mg/kg and KL from 0.14 to 0.08 L/mg; and as for apple pruning residues, qmax decreased from 7550 to 7300 mg/kg and KL from 0.09 to 0.06 L/mg, respectively. To study the effect of pH and ionic strength on the sorption behavior of cadmium by biosorbents, a batch experiment was conducted with various initial concentrations of Cd2+ (0 – 200 mg.L-1) with two biosorbents (sunflower stalks and apple pruning residues) in two pH (4, 8) levels and two ionic strengths (0.1 and 0.03 M). Sorption data were fitted to Langmuir, Temkin and Freundlich Equations. Results showed that both pH and ionic strength (IS) had significantly affected Cd sorption. Langmuir maximum mono layer adsorption (qmax) and binding energy value (KL) increased with increasing pH by two biosorbents. Sorption coefficients of Freundlich (KF, n) and Temkin (KT , A) indicated similar trends as well. But by increase in IS (from 0.03 to 0.1 M) all the sorption parameters decreased significantly. As for the case of sunflower stalks; with increase in ionic strength, qmax on the average, decreased from 8505 to 8150 mg/kg and KL from 0.14 to 0.08 L/mg; and as for apple pruning residues, qmax decreased from 7550 to 7300 mg/kg and KL from 0.09 to 0.06 L/mg, respectively.

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