Removal of chlorhexidine gluconate in presence of a cationic surfactant using acid functionalized activated carbon: Validation of multicomponent models. Issue 5 (October 2020)

• Record Type: Journal Article
• Authors: Banerjee, Debasree; Basu, Sankhadeep; Sarkar, Ujjaini
• Is Part Of: Journal of environmental chemical engineering. Volume 8:Issue 5(2020)
• Publication Date: 2020-10
• Subjects: Multicomponent adsorption -- Zeta potential -- Functionalized activated carbon -- Cationic surfactant -- Chlorhexidine gluconate -- Oxygenated surface functional groups; Chemical engineering -- Environmental aspects -- Periodicals; Environmental engineering -- Periodicals; Chemical engineering -- Environmental aspects; Environmental engineering; Periodicals; 660.0286
• DOI: 10.1016/j.jece.2020.104154
• Languages: English
• ISSNs: 2213-2929

Abstract

Graphical abstract: Mechanism of adsorption of chlorhexidine gluconate in presence of cetrimide. Highlights: HF and HCl functionalized activated carbons are synthesized for multicomponent adsorption of chlorohexidine and cetrimide. Adsorption of both chlorhexidine and cetrimide is in the order of FAC-HF > FAC-HCl > GAC. Max. adsorption capacity of FAC-HF for pure chlorohexidine and cetrimide: 349 g/g and 23 g/g respectively. Average removal of cetrimide: GAC (=36.64%), FAC-HCl (=47.09%) and FAC-HF (=75.74%). Electrostatic interactions along with surface complexation play a major role in the removal process. Abstract: Commercial antiseptic solutions containing a mixture of antibacterial agents such as, chlorhexidine gluconate, in presence of a cationic surfactant like cetrimide, are commonly used as floor, toilet and kitchen cleaning agents. Although a specific composition may be beneficial for disinfecting human beings, these are toxic to aquatic organisms, the plant biota and useful microorganisms present in soil and in municipal sewer pipes. In this study, functional modification of granular activated carbon (GAC) is carried out with hydrochloric and hydrofluoric acids in order to enhance the adsorption capacity of GAC for simultaneous removal of both chlorhexidine gluconate and cetrimide. Hydrofluoric acid functionalized activated carbon shows highest removal of both cetrimide and chlorhexidine gluconate (maximum adsorption capacitypure component chlorhexidine gluconate =349.0 g/g; maximum adsorption capacitypure component cetrimide =23.0 g/g). Average removal of cetrimide by GAC, FAC-HCl and FAC-HF are 36.64 %, 47.09 % and 75.74 % respectively. Surface charge of modified activated carbons is significantly altered as compared to unmodified GAC which provided an enhanced net available driving potential for the positive cetrimonium ions to reach the surface much faster as compared to the bulky chlorhexidine gluconate molecules. Cetrimide then undergoes pure physical adsorption through pore diffusion. However, chlorhexidine gluconate forms surface complexes with the functional groups as confirmed by the relative quantities of oxygenated surface functional groups and Fourier Transform Infrared (FT-IR) analysis. Intraparticle diffusion and Boyd plots show that film diffusion and not intraparticle diffusion is the rate controlling step.