Improvement of Water Quality Using Alginate/Montmorillonite Composite Beads

The aim of this study is to explore naturally occurring sorbents that have high affinity for heavy metal treatment. In this respect, series of polymer-clay composite beads that consists of Na-alginate and montmorillonite clay were prepared using CaCl2 as crosslinker. The prepared composite bead was characterized by scanning electron microscope (SEM). Removal of lead from aqueous solution using this bead was then studied in batch adsorption experiments. The amount of lead removed was found to increase as the percent of Na-alginate increase in the composite beads. The experimental results also showed that the equilibrium contact time was obtained within similar to 100 min with (t(1/2)) of 50% adsorption in less than 10 min. Lead adsorption was found to be strongly pH-dependent and display a maximum uptake capacity (244.6 mg/g) at pH 6 and minimum uptake (76.6 mg/g) at pH 1. Maximum lead adsorption was found to increase with increasing initial lead concentration in the feed solution and with decreasing temperature of experiment. Based on alginate-montmorillonite beads packed columns, a highly efficient method for Pb(II) removal from aqueous solution was developed. The effect of flow rate on adsorption of 100 mg/L Pb(II) in the packed-bed column was investigated by changing the flow rate between 0.5 and 2.5 mL min(-1). The recovery of 100 mg/L Pb(II) in the packed-bed column was found to be 100% at flow rates 0.5 and 1 mL min(-1) then lowered to be 93% and 84% at flow rates 1.5 and 2.5 mL min(-1),respectively. The effect of Pb(II) flow concentration ranging from 10 to 1000 mg/L on the adsorption of lead ions at constant flow rate 1.0 mL min(-1) was also studied using column procedure. Technical feasibility for the uses of the prepared composite beads for the treatment of actual polluted wastewater samples collected from some industrial cities in Egypt was investigated. The evaluation of the system was performed by a complete analysis of heavy metals in the wastewater samples before and after the treatment process. The results showed a promising possibility for producing wastewater of better quality using such prepared beads. (C) 2010 Wiley Periodicals, Inc. J Appl Polym Sci 119: 2371-2378, 2011