title: Enhancing adsorption capacity of toxic malachite green dye through chemically modified breadnut peel: equilibrium, thermodynamics, kinetics and regeneration studies.
abstract: Breadnut skin, in both its unmodified (KS) and base-modified (BM-KS) forms, was investigated for its potential use as a low-cost adsorbent for the removal of toxic dye, malachite green (MG). Characterization of the adsorbents was carried out using scanning electron microscope, X-ray fluorescence and Fourier transform infra-red spectroscopy. Batch adsorption experiments, carried out under optimized conditions, for the adsorption of MG were fitted using five isotherm models (Langmuir, Freundlich, Dubinin-Radushkevich, Temkin and Sips) and six error functions to determine the best-fit model. The adsorption capacity was greatly enhanced when breadnut skin was chemically modified with NaOH, leading to an adsorption capacity of 353.0 mg g(-1), that was far superior to most reported adsorbents for the removal of MG. Thermodynamics studies indicated that the adsorption of MG was spontaneous on KS and BM-KS, and the reactions were endothermic and exothermic, respectively. Kinetics studies showed that both followed the pseudo-second order. Regeneration experiments on BM-KS indicated that its adsorption capacity was still maintained at>90% even after five cycles. It can be concluded that NaOH-modified breadfruit skin has great potential to be utilized in real-life application as a low-cost adsorbent for the removal of MG in wastewater treatment.
authors.affiliation: a Department of Chemistry, Faculty of Science , Universiti Brunei Darussalam , Jalan Tungku Link, Gadong , Negara Brunei Darussalam.
authors.forename: Hei Ing
authors.initials: HI
authors.lastname: Chieng
authors.forename: Linda B L
authors.initials: LB
authors.lastname: Lim
authors.forename: Namal
authors.initials: N
authors.lastname: Priyantha
mesh_terms: D000327:Adsorption; D031622:Artocarpus / Q000737:chemistry*; D001673:Biodegradation, Environmental; D003198:Computer Simulation; D007700:Kinetics; D008422:Materials Testing; D008956:Models, Chemical; D059027:Recycling / Q000379:methods*; D012394:Rosaniline Dyes / Q000737:chemistry / Q000302:isolation & purification*; D012639:Seeds / Q000737:chemistry; D014462:Ultrafiltration / Q000379:methods; D014874:Water Pollutants, Chemical / Q000737:chemistry / Q000302:isolation & purification*; D018508:Water Purification / Q000379:methods*
chemical_list: D012394:Rosaniline Dyes; D014874:Water Pollutants, Chemical; C005095:malachite green
keywords: breadnut skin; equilibrium isotherms; kinetics; malachite green; regeneration