Green Route for the Removal of Pb from Aquatic Environment

Wastewater treatment/remediation is a very important process that has a great environmental and economic impact. Therefore, it is crucial to innovate different methods to remove pollutants of different sources from wastewater. This work was conducted in order to study the removal of lead (Pb+2) from wastewater using microspheres of composites of sodium alginate, cellulose and chitosan, as well as using a cost-effective green route through composites of sodium alginate and dried water hyacinth.

Molecular modeling at B3LYP/6-31g(d,p) was utilized to study sodium alginate, cellulose and chitosan. Sodium alginate was cross-linked with calcium chloride to form microspheres, then both sodium alginate/cellulose and sodium alginate/chitosan were also crosslinked as 50/50 to form microspheres. The roots of the aquatic plant water hyacinth in dry form were added to the cross-linked sodium alginate for up to 70%. SEM and FTIR were employed to study the surface of the prepared microspheres and their structures respectively. Atomic absorption spectroscopy was used to study the levels of Pb.

Molecular modeling indicated that the blending of such structures enhances their ability to bind with surrounding molecules owing to their ability to form hydrogen bonds. SEM results indicated that homogeneous structures of cellulose and chitosan are deformed when blended with sodium alginate, and FTIR confirmed the proper formation of the desired blends. Microspheres from sodium alginate showed the ability to remove Pb+2 from wastewater. SEM indicated further deformation in the morphology with the roughness of sodium alginate/water hyacinth microspheres, while FTIR confirmed the uniform matrices of the microspheres. The removal of Pb+2 was enhanced because of the addition of dried water hyacinth's roots.

Modeling, experimental and kinetic data highlight sodium alginate/water hyacinth root as a green route to remediate Pb+2 from wastewater.