Development of AgNPs-MWCNTs Adsorbent for Seawater Treatment

Abstract

Multi-walled carbon nanotubes (MWCNTs) were synthesized using Fe-Co/Al2O3 bimetallic catalyst synthesized via the wet impregnation method. Also, silver nanoparticles (AgNPs) was synthesized via the green synthesis route using extract from Piptadeniastrum africana (P. africana) leaves. The synthesized silver nanoparticles was then doped with MWCNTs to form (AgNPs-MWCNTs) nano adsorbent. The adsorbent produced was characterized using TGA, TEM, EDS and BET. The adsorption efficiency and antibacterial activity of the adsorbent was tested on sample of seawater collected from Lagos, Nigeria. Evaluation of antimicrobial potentials of the nano-formulated adsorbent was carried out via bacteria counts. Also, adsorption capacity towards selected parameters of nano-formulated adsorbent treated seawater were investigated in order to determine the adsorption capacity of the nanocomposite. Parameters such as pH, turbidity, conductivity, TSS, TDS, COD, BOD, DO and ions such as Cl-, Na+, Mg2+, Ca2+, F-, SO42-, HCO3 - Br-, Sr2+ and K+ were analysed. The antibacterial activity of the adsorbent was investigated against microorganisms Salmonella typhimurium, Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, fungi and non-pathogenic bacteria. Results obtained show that the adsorbent was very effective in the removal of dissolved ions, contaminants and microorganisms present in the seawater. The dissolved ions, microorganisms and other pollutant in the water were reduced to within the limits recommended in the National Standard for Drinking Water Quality guidelines (NSDWQ). It can be concluded that AgNPs-MWCNTs adsorbent have superior potential for seawater treatment and thus, recommended as a cost effective and energy saving alternative for seawater treatment.