Simultaneous Removal Of Cadmium Ions Research Articles

Simultaneous removals of cadmium(II) ions and reactive yellow 4 dye from aqueous solution by bone meal-derived apatite: kinetics, equilibrium and thermodynamic evaluations

The simultaneous removal of Cadmium ions and reactive yellow 4 dye (RY4 dye) by bone meal-derived apatite (BMDA) were investigated in a batch process. The structural elucidation of the prepared BMDA was done using TEM, XRD, FT-IR and EDX to evaluate the structures of the adsorbent. Different experimental features such as the agitation time, BMDA dosage, temperature, initial adsorbate concentration and pH of the solution were examined on the uptake pattern of the pollutants. The mechanism of adsorption was examined with Elovich, pseudo-first-order, intraparticle diffusion and pseudo-second-order kinetic models, while Langmuir, Dubinin-Radushkevich (D-R), Freundlich and Tempkin isotherms were exploited in order to describe the behaviour of the equilibrium process. Analysis from XRD revealed peaks corresponding to single phase apatite powder, while the various forces responsible for the interactions between the BMDA surface and the pollutants were obtained to CO32−, OH− and PO43− as observed by FT-IR analysis. SEM and TEM investigations confirmed a round-like morphology which agglomerated together upon the adsorption of pollutants.The kinetic modelling of the adsorption data were well illustrated with the pseudo-first-order model with correlation coefficient (R2) values ranging from 0.997 to 0.999. Isotherms studies revealed that best fit was achieved with Langmuir isotherm with adsorption capacities of 94.85 and 116.16 mg/g for RY4 dye and Cd(II) ions respectively. Thermodynamic study signified the uptake of the pollutants to be spontaneous, feasible and endothermic in nature. The values of entropy change (ΔS) for the sorption processes calculated are 86.57 and 60.16 J/mol/K for Cd(II) and RY4 dye, respectively.

Local, cheep and nontoxic activated carbon as efficient adsorbent for the simultaneous removal of cadmium ions and malachite green: Optimization by surface response methodology

The focus of present study is on the optimization of variables influencing the simultaneous removal of Cd2+ ion and malachite green (MG) from aqueous solution by activated carbon (AC).The AC was prepared from oak wood and then it was characterized using different techniques such as SEM, BET, FT-IR and Boehm titration. The effects of variables such as pH, initial dye concentration, cadmium ion concentration, adsorbent mass (g) and contact time on the adsorption of Cd2+ ion and MG were examined by central composite design (CCD). The experimental data for single solution of either of Cd2+ ion and MG followed the Langmuir model. The adsorption of Cd2+ ion in binary mixture followed the Freundlich model. The rate of adsorption and mass transfer kinetics exactly can be elucidated by pseudo second order model.

Simultaneous removal of cadmium ions and phenol from water solution by pulsed corona discharge plasma combined with activated carbon

In this paper, an integrated approach, the pulsed corona discharge plasma combined with granular activated carbon (PCDP/GAC), is used for the simultaneous removal of cadmium ions (Cd2+) and phenol in wastewater. Experimental results show that 69.0% Cd2+ and 87.3% phenol can be simultaneously removed from the PCDP/GAC treatment system after 60min. This removal efficiency is 27.2% and 11.4% higher than in the GAC adsorption system, respectively, and 65.8% and 60.6% higher than in the PCDP treatment system, respectively. An increasing pulsed voltage is favorable for removal of Cd2+ and phenol. The removal efficiency of Cd2+ and phenol is the highest with oxygen as the feeding gas. At the same input power and an increasing initial phenol concentration, the removal efficiency of Cd2+ and phenol decreases. Scanning electron microscopy and energy-dispersive X-ray spectroscopy show that Cd2+ amount produced on GAC by the discharge treatment in the PCDP/GAC system is higher than that in the GAC adsorption system. Fourier transform infrared spectroscopy shows that OH, CH, and CC bonds on GAC are cleaved, whereas ArOC and CO groups increase during the PCDP treatment. A possible removal mechanism of Cd2+ and phenol in such a system is proposed.

Simultaneous removal of cadmium ions and phenol with MEUF using SDS and mixed surfactants

Micellar-enhanced ultrafiltration (MEUF) is a promising technology to remove metal ions and organic contaminants simultaneously from wastewater. A laboratory experiment was conducted to evaluate the efficiency of a MEUF operation for the removal of Cd2+ and phenol using pure SDS and mixed surfactants (Triton X-100/SDS). In pure SDS system, with the increase of the feed SDS concentration, a significant rise in Cd2+ rejection was obtained, which peaked at 97.0% with initial SDS concentration being 8.0mM. Nevertheless, the phenol rejections only kept moderately increasing from 14.5% to 40.0%. In mixed Triton X-100/SDS system, the rejections of Cd2+ and phenol were both enhanced by the moderate addition of nonionic surfactant for the same total feed surfactant concentration as the pure SDS system. With the increase of the molar ratios of Triton X-100 to SDS (α), Cd2+ rejection increased slightly with α ranging from 0 to 0.8, and peaked at 91.3%. And the phenol rejection kept increasing from 27.7% to 42.4% when α was less than 1.0 followed by slight decrease to 40.2% at α=1.5. Moreover, the SDS dosage and the surfactant(s) concentration in permeate were reduced efficiently. The permeate flux of MEUF with mixed surfactants was lower than that with pure SDS.