@article { author = {}, title = {INVESTIGATION OF FACTORS AFFECTING REMOVAL OF NICKEL BY PRE-TREATED WALNUT SHELLS USING FACTORIAL DESIGN AND UNIVARIATE STUDIES}, journal = {Iranian Journal of Science and Technology Transactions of Civil Engineering}, volume = {38}, number = {C1+}, pages = {309-324}, year = {2014}, publisher = {Shiraz University}, issn = {2228-6160}, eissn = {}, doi = {10.22099/ijstc.2014.1872}, abstract = {The main objective of this study was to identify the operating conditions whichinfluence Ni(II) adsorption onto pre-treated walnut shell. For this purpose, in the first step, a seriesof experiments were planned according to a full 24 factorial experimental design. The factorsinvestigated here were solution pH, adsorbent dose, the initial concentration of nickel, andtemperature. The results predicted using the factorial regression model showed high values ofregression coefficient (R2=99.55%), indicating good agreement with the experimental data. It wasobserved that the main effect of all the factors, besides the interaction of pH and metalconcentration, were significant within a 95% confidence level, while for the conditions tested inthis study, the pH of the solution was the most influential parameter in the removal of nickel.In the second stage, univariate studies were conducted to validate the results obtained in thefirst part and also to find the conditions that would give the highest removal of nickel fromaqueous solutions. The univariate experimental results provided evidence supporting the sorptiondata obtained in the factorial design phase of this study. Under the optimal conditions obtained, thenickel ion adsorption equilibrium could be satisfactorily described by the Langmuir isothermmodel. The maximum pre-treated walnut shell adsorption capacity for Ni(II) was 8.57 mg/g. Thekinetics of Ni(II) adsorption onto pre-treated walnut shell followed the pseudo second-ordermodel.}, keywords = {Adsorption,experimental design,isotherm,Ni(II),Kinetic,pre-treated walnut shell}, url = {https://ijstc.shirazu.ac.ir/article_1872.html}, eprint = {https://ijstc.shirazu.ac.ir/article_1872_86e82d033345734099e2049d0f150afc.pdf} }