Enhanced boron adsorption using PVA-modified carbonaceous materials

• Published in: Composite interfaces 2014-01, Vol.21 (7), p.639-650
• Main Authors: Ismanto, A.E., Liu, J.C.
• Format: Article
• Language: English
• Subjects: activated carbon; adsorption; boron; carbon nanotubes (CNTs); polyvinyl alcohol (PVA); surface modification; wastewater
• ISSN: 0927-6440; 1568-5543
• DOI: 10.1080/15685543.2014.927288

Activated carbon and carbon nanotubes (CNTs) were modified with polyvinyl alcohol (PVA) and used for boron removal from aqueous solution. Results from the Boehm titration showed significant increase of the total acidic surface functional groups of both activated carbon and CNTs after PVA modification, and demonstrated that PVA was successfully grafted onto adsorbent surfaces. BET surface area of activated carbon decreased significantly after PVA modification, while only limited decrease was found for PVA-modified CNTs. The adsorption kinetics of boron could be described by pseudo-first-order and pseudo-second-order models. Langmuir adsorption isotherm fitted the equilibrium adsorption well. Significant enhancement of boron adsorption onto PVA-modified activated carbon and CNTs was found as evidenced by the remarkable increase in adsorption constant. In general, boron adsorption increased with increasing pH. It was proposed that enhanced boron adsorption onto PVA-modified CNTs was via complex formation between boron and cis-diol groups of the PVA-modified adsorbents, whereas physical force was the driving force for the original ones.