The effects of carbon disulfide driven functionalization on graphene oxide for enhanced Pb(II) adsorption: Investigation of adsorption mechanism

• Published in: Chemosphere (Oxford) 2020-06, Vol.248, p.126078-126078, Article 126078
• Main Authors: Lian, Qiyu, Ahmad, Zaki Uddin, Gang, Daniel Dianchen, Zappi, Mark E., Fortela, Dhan Lord B., Hernandez, Rafael
• Format: Article
• Language: English
• Subjects: Adsorption; Carbon Disulfide - chemistry; Carbon sulfide; Graphene oxide; Graphite - chemistry; Kinetics; Lead - analysis; Pb(II) adsorption; Surface modification; Surface Properties; Water Pollutants, Chemical - analysis; Water Purification - methods; XPS spectra
• ISSN: 0045-6535; 1879-1298
• DOI: 10.1016/j.chemosphere.2020.126078

The surface properties of graphene oxide (GO) have been identified as the key effects on the adsorption of Pb(II) from aqueous solutions in this study. This study reveals the effect of the surface reactivity of GO via Carbon Disulfide (CS2) functionalization for Pb(II) adsorption. After successfully preparing CS2 functionalized GO (GOCS), the specific techniques were applied to investigate Pb(II) adsorption onto GOCS. Results indicated that the new sulfur-containing functional groups incorporated onto GOCS significantly enhanced Pb(II) adsorption capacity on GOCS than that of GO, achieving an improvement of 31% in maximum adsorption capacity increasing from 292.8 to 383.4 mg g−1. The equilibrium adsorption capacity for GOCS was 280.2 mg g−1 having an improvement of 83.2% over that of 152.97 mg g−1 for GO at the same initial concentration of 150 mg L−1 under the optimal pH of 5.7. Moreover, the results of adsorption experiments showed an excellent fit to the Langmuir and Pseudo-Second-Order models indicating the monolayer and chemical adsorption, respectively. The mechanism for Pb(II) adsorption on GOCS was proposed as the coordination, electrostatic interactions, cation-pi interactions, and Lewis acid-base interactions. The regeneration study showed that GOCS had an appreciable reusability for Pb(II) adsorption with the adsorption capacity of 208.92 mg g−1 after five regeneration cycles. In summary, GOCS has been proved to be a novel, useful, and potentially economic adsorbent for the high-efficiency removal of Pb(II) from aqueous solutions. [Display omitted] •The surface reactivity of GO was successfully enhanced by CS2 functionalization.•-(C=S)-S- was introduced onto the GO and identified by FTIR and XPS.•GOCS showed the improvement of 83.2% over GO in adsorption capacity for Pb(II).•The maximum adsorption capacity of for GOCS was found to 383.4 mg g−1.•The proposed mechanism was the interactions between Pb(II) and functional groups.