Okra Leaves—Agricultural Waste for the Removal of Cr(III) and Cr(VI) from Contaminated Water

Abstract

The present study demonstrates the sorptive efficiency of okra leaves for the Cr(III) and Cr(VI) in aqueous system. The batch dynamic sorption method was carried out as the function of the pH of the solution, sorbent doze, initial bulk concentration, shaking speed and contact time. The experimental data were examined by Langmuir and Freundlich isotherms. Cr(III) at pH-4.0 and Cr(VI) pH-2.0 showed a maximum sorption capacities 221.17 mg/g and 81.94 mg/g respectively. Kinetically experimental data of both chromium species were well fitted to pseudo second order rate, Elovich, Morris-Weber and Richenberg equations. Positive values of enthalpy change and negative values of Gibbs free energy indicated the endothermic and spontaneous nature of sorption reaction respectively. The developed method was applied to real ground water samples (affected by industrial wastewater). Up to 92.15% of chromium metal was removed from the real water samples.

Competitive sorption of nickel, copper, lead and cadmium on okra leaves (Abelmoschus esculentus)

“…Table 4 shows that Gibbs free energy (∆G) values of all metals are negative, means sorption reaction of metal ions on okra leaves sorbent was spontaneous (i.e sorption forces are quite strong to overcome the potential barrier ). Increase of negative value with the increase of temperature favour the sorption process (Khaskheli et al, 2016). In other words it can be said that the degree of spontaneity increases with increasing the temperature (Thajeel, 2013).…”

“…The affect of concentration on the amount of metal sorbed onto the surface was calculated and the data were evaluated using Langmuir, Freundlich (Khaskheli et al, 2016), D-R, Flory-Huggins and Halsey isotherm equations (Basar, 2006;Vijayaraghavan et al, 2006). All equations were analyzed in following linearized form: ), qmax is the maximum amount of ions sorbed, KL is the Langmuir constant related to the binding energy of solute, KF and 1/n are Freundlich constants representing sorption capacity and sorption intensity, respectively; є is polanyi potential and equal to RTln(1+1/Ce), T is temperature and R is general gas constant; β is related to the mean free energy of sorption per mole of the sorbent when it is transferred from infinite distance in the solution to the surface of the solid by equation:…”

The utilization of okra leaves as an agricultural waste for the removal of As(III) and As(V)

“…Thermodynamic study helps in estimating the nature and feasibility of the sorption reaction (Iftikhar et al, 2009;Khaskheli et al, 2016;Ladeira et al, 2004). Thermodynamic parameters (enthalpy change, entropy change and Gibbs free energy) were calculated by using the following equation.…”

Analytical chemistry in technical approaches: immobilization of biosorbent waste containing heavy metals in cemented materials

“…[2], Dimocarpus longan [3], and activated carbon from Quercus robur leaves [4], activated carbon from Phoenix dactylifera L. leaves [5], Sauropus androgynus (L.) Merr. [6], Camellia sinensis leaves [7], Citrus × paradisi peelings [8], Abelmoschus esculentus leaves [9], etc., as well as geomaterials such as clay, zeolite, and perlite [5,7,[9][10][11].…”