Chemically activated Ipomoea carnea as an adsorbent for the copper sorption from synthetic solutions

Abstract

An indigenously prepared zinc chloride activated Ipomoea carnea (morning glory), a low-cost and abundant adsorbent, was used for removal of Cu(II) ions from aqueous solutions in a batch adsorption system. The chemical activating agent ZnCl 2 was dissolved in deionised water and then added to the adsorbent in two different ratios 1:1 and 1:0.5 adsorbent to activating agent ratio by weight. Studies were conducted as a function of contact time, initial metal concentration, dose of adsorbent, and pH. Activated Ipomoea carnea (AIC) were characterised using scanning electron microscopy (SEM), iodine number and methylene blue number. High iodine numbers indicates development of micro pores with zinc chloride activation. Maximum adsorption was noted within pH range 6.0(±0.05). Adsorption process is fast initially and reaches equilibrium after about 4 hours. The kinetic data were analysed using pseudo-first-order and pseudo-second-order models. The pseudo-second-order kinetic model was found to agree well with the experimental data. Adsorption equilibrium data were analyzed using Langmuir and Freundlich isotherm models. The Langmuir model represented the sorption process better than the Freundlich model. Based on the Langmuir isotherm, the monolayer adsorption capacity of Cu(II) ions was 7.855 mg g −1 for AIC (1:1) and 6.934 mg g −1 for AIC (1:0.5). Nomenclature aRadius of spherical adsorbent particles (m) C 0 Concentration of Cu 2+ before adsorption (mg/l) C e Equilibrium concentration of Cu 2+ in solution (mg/l) C r Concentration of Cu 2+ after adsorption (mg/l) D eff Effective diffusion coefficient (m 2 /s) D 2 Particle diffusion coefficient (m 2 /s) F Fractional attainment of equilibrium at time t K Freundlich constant representing multilayer adsorption capacity (mg/g) K f Pseudo first-order rate constant (min −1 ) K id Initial rate of intraparticle diffusion (mg/(g min 0.5 )) K L Langmuir constant representing adsorption intensity (l/mg) K s Pseudo second-order rate constant (g/mg min) M Mass of the adsorbent (g) n Freundlich constant representing adsorption intensity (g/l) q e Adsorption capacity at equilibrium (mg/g) q tAdsorption capacity at any time t (mg/g) Q 0 Langmuir constant representing maximum monolayer adsorption capacity (mg/g) 76 Adsorption (2010) 16: 75-84 R 2 Regression coefficient t Contact time (min) V Volume of adsorbate solution (l)

Comparative study on the biosorption of Pb(II), Cd(II) and Zn(II) using Lemon grass (Cymbopogon citratus): Kinetics, isotherms and thermodynamics

“…The difference in biosorption capacity q (mgg -1 ) at the same initial metal ion concentration and contact time may also be attributed to the difference in their chemical affinities and ion exchange capacity, with respect to the chemical functional group on the surface of the biosorbent. This trend has been reported for other biosorbents (Miranda et al, 2010).…”

Biosorption of Ni(II), Cr(III), and Co(II) from Solutions Using Acalypha hispida Leaf: Kinetics, Equilibrium, and Thermodynamics

“…e difference in biosorption capacity (mg g − ) at the same initial metal ion concentration and contact time may also be attributed to the difference in their chemical affinities and ion exchange capacity, with respect to the chemical functional group on the surface of the biosorbent. is trend has been reported for other biosorbents [23].…”

Investigation on Cu(II) adsorption on cobalt silicate precipitation tube (CSPT) in aqueous medium

“…It is apparent from the discussion above that loading capacity of an adsorbent at a particular temperature is a function of both adsorbent weight and initial adsorbate concentration. This is noted with gratification that Cu(II) loading capacity of CSPT is quite high by both isotherm, as well as "non-isotherm" approach, and this was compared with literature data for various adsorbents [12][13][14][15][16]. Table 3 lists some of the high Cu(II) loading capacities available in the literature along with the one obtained from the present study.…”

“…where slope (K id ) and intercept (S) are the measures of intraparticle diffusion and surface sorption, respectively [16]. Cu(II) adsorption data on CSPT at three different temperatures were plotted using Weber-Morris equation and slopes and intercepts obtained there from have been listed in Table 5.…”