Removal of linuron from water by natural and activated bentonite

The sorption of linuron on bentonite desiccated at 110 degrees C untreated, and acid-treated with H2SO4 solutions over a concentration range between 0.25 M and 1.00 M from aqueous solution at 25 degrees 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 linuron of different concentrations (C = 4.97 mg dm(-3) and C = 7.63 mg dm(-3)). The experimental data points have been fitted to the Langmuir equation in order to calculate the sorption capacities (X-m) of the samples; X-m values range from 0.02 g kg(-1) for the untreated bentonite [B-N] up to 0.20 g kg(-1) for the sample acid-treated with the 1.00 M H2SO4 solution. The removal efficiency (R) has also been calculated; R values ranging from 15.86% for the [B-N] sample up to 41.54% for [BA(1.00)]. The batch experiments show that the acid-treated bentonite is more effective than the natural bentonite in relation to sorption of linuron. The column experiments show that the B-A(1.00) sample might be reasonably used in removing linuron, the column efficiency increasing from 61.8% for the C = 7.63 mg dm(-3) aqueous solution of linuron up to 77.6% for the C = 4.97 mg dm(-3) one. (C) 1999 Society of Chemical Industry.