Open AccessDetoxification of Wastewater by Paw–Paw (Carica papaya L.) Seeds Adsorbents
Author(s) -
Ntaote David Shooto,
Eliazer Bobby Naidoo
Publication year - 2019
Publication title -
asian journal of chemistry/asian journal of chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.145
H-Index - 34
eISSN - 0975-427X
pISSN - 0970-7077
DOI - 10.14233/ajchem.2019.22051
Subject(s) - biosorption , chemistry , sorption , adsorption , endothermic process , nuclear chemistry , langmuir , metal ions in aqueous solution , aqueous solution , langmuir adsorption model , carica , chromatography , metal , botany , organic chemistry , biology
The present work reports the biosorption studies of metal ions viz., Pb(II) and Cu(II) from aqueous solution onto paw-paw seeds (PPS), acid treated paw-paw seeds (ATPPS) and base treated paw-paw seeds (BTPPS) adsorbents by batch method. A series of tests were carried to evaluate the effect of the system parameters, i.e. adsorbent dosage, initial concentration, temperature and contact time. The obtained kinetic data showed that the pseudo first order model best fitted the biosorption of both metal ions with (r2) values of 0.9918, 0.9674 and 0.9463 for Cu(II) onto PPS, ATPPS and BTPPS, respectivelyand for Pb(II) 0.8513, 0.8686 and 0.9434 onto PPS, ATPPS and BTPPS respectively. Estimated surface adsorption of intra-particle diffusion estimated that surface sorption dominated. Thermodynamic parameter (ΔGo) gave negative values indicating that the biosoption processes were spontaneous and feasible. ΔHo gave positive and negative values indicating that some biosorption processes were endothermic and some exothermic. Isotherm data indicated that Langmuir best described the biosorption. The reusability of PPS, ATPPS and BTPPS adsorbents was evaluated up to five cycles without showing significant drop in sorption efficiency.