Trace metal modified engineered carbon nano tubes for arsenic removal

Abstract

Carbon nanotubes were used to study the adsorption behavior of arsenic (As) found in aqueous media and its effect in the adsorption efficiency when they are modified with certain trace metals onto the multi- walled carbon nanotubes (MCNTs) as adsorbents. Iron, titanium, silver, gold, copper were made to be impregnated on the CNTs for this study. The effect on the surface functional group of the carbon nanotubes were further studied on the removal of As. Batch experiments were performed to study the effect of the As removal in the aqueous media, the independent variables considered are pH, contact time and agitation speed. The morphology of the CNTs were characterized by using field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) which indicates the dimensions of the adsorbents and the impregnation were seen before and after the adsorbents were made. Results of the study showed that iron and titanium impregnated on the surface of the CNT has the highest As removal percentage compared to pure CNT and the functionalized CNT with carboxylic group. Almost 70% of the As was removed from the water that contained 1 mg/L initial arsenic contamination. The highest removal was at pH 3, contact time of 24 hours and agitation speed of 200 RPM. Part of the study is also dedicated to investigate the effect of dosage in the removal of arsenic from water.