Removal of Heavy Metals from Aqueous Solutions using Ze0lite(LTA) Synthesized from Sudanese Clay

Abstract

This study was carried out to synthesize zeolite LTA fiom Sudanese clay, fiom the banks of the Blue Nile in Bahary province. The clay was purified and analyzed using X-ray Diffiaction (XRD), Scanning Electron Microscopy (SEM) and X-ray Fluorence (XRF) methods. The results of the chemical analysis showed that the starting material (clay) is montmorillonite . Also those results showed that four types of zeolite were successfully synthesized (Vauxite, Alunite zeolite A and zeolite LTA) .The controlled conditions used were (440, 550, 650 and 750 “C and lh) for the clay calcination, 100°C and 2h for the reaction, 12h for fonnation of zeolite crystals and 5 M NaOH for the alkali concentration. The differences in zeolite types is due to different temperatures of calcination of the clay. The results indicated that zeolite LTA was the best synthesized sample. To determine the most effective zeolite sample, the samples have been tested for the removal of lead ion (10 mg/l) fiom aqueous solution. The concentration of lead was measured before and afier treatment using Inductively Coupled Plasma. The analysis showed that zeolite LTA was the best in the removal of lead with 99.42%, followed by zeolite A 81.22%, Alunite 73.14% and Vauxite 63.14%. On this basis zeolite LTA was chosen as the best sample for use in the removal of heavy metals from aqueous solutions. The factors affecting the removal of ions such as dose of zeolite LTA, time, initial concentration as well as pH were studied. The results showed that zeolite LTA is very effective for removal of tested ions(Pb2+ , Zn”, Cu“ , Ni”) from aqueous solutions, and the removal percent at the first 30min. was high . It was found that the effectiveness of zeolite LTA continued for two hours and then the zeolite was saturated and lost the ability to remove heavy metal ions from aqueous solution. The results indicated that, with the increase of pH (from 1 to 5) the efficiency of zeolite in removal of those ions increased. The percentage of ia -