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Removal of 1,1′-Dimethyl-4,4′bipyridyl Dichloride from Aqueous Solution by Natural and Activated Bentonite
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1997
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EngineeringLeachingOrganic ChemistryChemistryMineral ProcessingChemical EngineeringEnvironmental ChemistryNatural BentoniteMineral-fluid InteractionH2so4 SolutionsWater TreatmentAnalytical ChemistryAqueous SolutionChemisorptionClay Mineral1,1′-Dimethyl-4,4′bipyridyl DichlorideEnvironmental EngineeringWater PurificationEnvironmental RemediationRemoval EfficiencyActivated Bentonite
The sorption of 1,1′-dimethyl-4,4′bipyridilium dichloride (paraquat) on bentonite desiccated at 110°C untreated, and acid-treated with H2SO4 solutions over a concentration range between 0·25 M and 1·00 M, from aqueous solution at 30°C has been studied by using batch experiments. In addition, column experiments were carried out with the bentonite sample treated with the 1·00 M H2SO4 solution [B-A(1·00)] by using two aqueous solutions of paraquat of different concentrations (C = 29·40 mg dm−3 and C = 65·38 mg dm−3). The experimental data points have been fitted to the Langmuir equation in order to calculate the sorption capacities (Xm) of the samples; Xm values range from 1·35×105 mg kg−1 for the sample acid-treated with 0·375 M H2SO4 [B-A(0·375)] up to 1·96×105 mg kg−1 for the untreated bentonite [B-N]. The removal efficiency (R) has also been calculated; R values ranging from 44·61% for the [B-A(0·375)] sample up to 67·23% for B-N. The batch experiments show that the natural bentonite is more effective than the acid-treated bentonite in relation to sorption of paraquat. The column experiments show that the B-A(1·00) sample might be reasonably used in removing paraquat, the column efficiency increasing from 37·55% for the C = 65·38 mg dm−3 aqueous solution of paraquat up to 66·58% for the C = 29·40 mg dm−3 one. © 1997 SCI.