Effect of chemical extractants on the biosorptive properties of pine cone powder: Influence on lead(II) removal mechanism

AbstractThis study examines the changes in surface properties and lead(II) adsorption mechanism of pine cone powder modified using varying ratios of toluene–ethanol mixtures.Increasing the ratio of toluene in the extractant mixture increased formation of esters and iodine capacity of the material, but reduced carboxylate ions and surface charge. Values of surface charge and iodine capacity showed no relationship with the bulk densities. Maximum lead(II) adsorption was observed for the 2:1 toluene–ethanol modified sample. Lead(II) ions adsorption was inversely related to surface charge and directly related to iodine capacity.Ion-exchange was the dominating mechanism followed by chemisorption. Physical adsorption was higher in the sample modified with the 2:1 mixture which also had the least surface negative charge. Shifts in peaks of FTIR spectra indicate that unbounded –OH and acidic groups were responsible for lead(II) bonding and the contribution of these groups were different for each sample

Sorption dynamics and isotherm studies of methylene blue uptake on to palm kernel fibre

[[abstract]]The effect of temperature on the sorption of methylene blue from aqueous solution onto palm kernel fibre has been studied. Batch kinetics and isotherm studies were performed at temperatures ranging from 299 to 339 K. The kinetic data were studied in terms of the pseudo-first-order and pseudo-second-order kinetic models and the Bangham and intraparticle diffusion models. The pseudo-second-order model best described the sorption process and was employed in predicting the rate constant, equilibrium sorption capacity and the initial sorption rate with effect of temperature. In addition activation energy of sorption has also been determined based on the pseudo-second-order rate constant. The isotherm data was analyzed by the Langmuir and Freundlich isotherms. Palm kernel fibre was found to have a Langmuir monolayer capacity of 233.41 mg g?1 at 299 K. The adsorption is endothermic at ambient temperature and the computation of the thermodynamic parameters, H?, S? and G? indicates that the sorption was favourable at all temperatures

Equilibrium sorption of anionic dye from aqueous solution by palm kernel fibre as sorbent

[[abstract]]Palm kernel fibre was investigated for its ability to perform as a suitable sorbent for anionic dye from aqueous solution. The effect of sorbent dose and temperature was investigated using a batch sorption technique. The results revealed the potential of palm kernel fibre, an agricultural waste, as a low-cost sorbent for the anionic dye examined. The isotherm data were closely fitted to the Langmuir equation and the dye sorption capacity of palm kernel fibre increased as the sorbent dose decreased. Maximum saturated monolayer sorption capacity of palm kernel fibre for 4-bromoaniline-azo-1,8-dihydronaphthalene-3,6-disodiumsulphate was 38.6 mg/g. Thermodynamic parameters such as change in the free energy, the enthalpy, and the entropy were also evaluated. In addition, relationships between sorbent dose and Langmuir constants were developed and are presented

Effect of temperatures and pH on Methyl violet biosorption by mansonia wood sawdust

[[abstract]]In this study, the effect of temperature on the equilibrium biosorption of methyl violet dye from aqueous solution using Mansonia wood sawdust was studied. The equilibrium biosorption data were analyzed using three widely applied isotherm models; Langmuir, Freundlich and Redlich–Peterson isotherm. The fit of three linear Langmuir isotherm forms, the Freundlich isotherm, and the Redlich–Peterson isotherm were determined using linear and the non-linear methods. Langmuir isotherm parameters obtained from the three Langmuir linear equations by using linear method were dissimilar, except, when the non-linear method was used. Best fits were yielded with Langmuir and Redlich–Peterson isotherms. The methyl violet biosorption was strongly dependent solution pH and percentage dye removal became significant above pH 7, which was slightly higher than the pHPZC of the sawdust material. In addition, various thermodynamic parameters, such as DG , DH , and DS were calculated. Results suggested that the biosorption was a spontaneous and endothermic process

Kinetic biosorption study of cadmium onto coconut copra meal as biosorbent

[[abstract]]The sorption of cadmium ions on an agricultural by-product, coconut copra meal, was investigated. A batch sorption model, based on the assumption of the pseudo-second-order mechanism, was applied to predict the rate constant of sorption, the equilibrium sorption capacity and the initial sorption rate with the effect of initial cadmium concentration and temperature. Activation energy of sorption was determined based on the pseudo-secondorder rate constants. In addition, the experimental results were analysed by pseudo-Langmuir, pseudo-Freundlich and pseudo-Redlich-Peterson isotherms based on pseudo-second order kinetic expression constant. Both pseudo-Langmuir and pseudo-Redlich-Peterson isotherms were found to represent the measured sorption data well. According to the evaluation using the pseudo-Langmuir equation, the monolayer sorption capacity was obtained to be 2.59 mg/g

Effect of pH on cadmium biosorption by coconut copra meal

[[abstract]]Biosorption of cadmium ion by coconut copra meal, an agricultural waste product was investigated as a function of initial solution pH and initial cadmium concentration. Pseudo-second-order kinetic analyses were performed to determine the rate constant of biosorption, the equilibrium capacity, and initial biosorption rate. Cadmium biosorption by copra meal was found to be dependent on the initial solution pH and initial cadmium concentration. Ion exchange occurred in the initial biosorption period. In addition, mathematical relationships were drawn to relate the change in the solution hydrogen ion concentration with equilibrium biosorption capacity, initial cadmium concentration, and equilibrium biosorption capacity