Potential Low-cost Adsorbent For Removal Research Articles

Biochar Derived from Sesbania sesban Plant as a Potential Low-Cost Adsorbent for Removal of Methylene Blue

In this study, biochar made from the Sesbania sesban plant, under slow pyrolysis at 300°C was used to adsorb methylene blue (MB) in aqueous solution. The biochar properties were clarified by diverse analytical methods such as FTIR, SEM, and BET. The results indicated that the surface of biochar was relatively smooth, had porous texture, and stacked evenly. In addition, the biochar had a large specific surface area of 561.8 m2/g and the pHpzc value was 6.9. The effect of adsorbent dosage, initial pH, contact time, and concentration of dye solution on biochar were investigated. The optimum conditions for MB adsorption were found at the MB concentration of 50 mg/L, initial pH of 11, biochar mass of 0.6 mg, and contact time of 30 min. Under these optimal conditions, MB dye removal efficiency was above 90%. Adsorption isotherm data were fitted with the Langmuir isotherm model (R2=0.897) suggesting the adsorption was monolayer, and its maximum adsorption capacity was about 6.6 mg/g. The adsorption kinetic models showed that the linear pseudo-second-order by R2=0.999 was well fitted. The results indicated the enormous potential of Sesbania sesban plant to produce biochar as a low-cost and rather high-effective adsorbent for dye removal from wastewater as well as water quality improvement.

The Efficiency of Cactus Leaves and Wood Charcoal as a Potential Low-Cost Adsorbent for Removal of Toxic Heavy Metals from Industrial Effluents

Presence of toxic heavy metals in the environment is of great concern due to their persistence in nature and chronic adverse effects on human health and the environment. Present paper tries to evaluate the efficiency of cactus leaves ( Opuntia f. indica ) and activated carbon made from acacia etbiaca as an adsorbent for the removal of heavy metal pollutants such as cadmium, lead and chromium from water. Adsorption properties such as size, dose, initial concentration and time of contact for cadmium, lead and chromium were studied through batch method. Before removing the toxic heavy metals (Cd, Pb and Cr), the fresh unpeeled cactus leaves (adsorbent) and activated carbon were washed with distilled water to eliminate the turbidity and smell from fresh unpeeled cactus. To describe the equilibrium isotherms, the experimental data were analyzed by the Langmuir and Freundlich isotherm models. Thus, the Freundlich model gave the best correlation with the experimental data. Therefore, the findings indicated that the cactus and activated carbon made locally from acacia etbiaca were found to be effective and low-cost alternative adsorbents for the removal of toxic heavy metals from industrial effluents. The preparation method allowed the use of these materials by local industries for effective remediation of pollution by removing heavy metals from their effluents. Keywords : Cactus leaves; Acacia etbiaca ; Heavy metals; Adsorption, Industrial effluents; Water purification.

Hard coal as a potential low-cost adsorbent for removal of 4-chlorophenol from water.

The potential use of raw hard coals as low-cost adsorbents for the removal of 4-chlorophenol (4-CP) from aqueous solutions was examined. The effect of experimental parameters such as the pH and salt presence was evaluated. The kinetic studies showed the equilibrium time was found to be 2 h for all of the adsorbents and that the adsorption process followed the pseudo-second order kinetic model. The adsorption isotherms of the 4-CP on the hard coals were fitted to the Langmuir, Freundlich, Langmuir-Freundlich, Sips and Redlich-Peterson equations. Based on the results obtained, hard coals appear to be a promising adsorbent for the removal of some hazardous water pollutants, like 4-CP and related compounds.

Removal of Crystal Violet from Aqueous Solution by Adsorption onto Eggshells: Equilibrium, Kinetics, Thermodynamics and Artificial Neural Network Modeling

The feasibility of utilizing eggshells as a potential low-cost adsorbent for removal of hazardous Crystal violet dye from aqueous solution was investigated. Employing a batch experimental set-up, the effect of operational parameters such as adsorbent dose, initial solution pH, initial dye concentration and temperature on the dye removal process was studied. The optimum conditions for decolorization of the dye solution were: initial dye concentration = 50 mg L−1, pH = 8.0 and adsorbent dose = 30 g L-1. The temperature had a significant impact on the adsorption process. The adsorption process followed pseudo second-order kinetics while the adsorption equilibrium data well fitted to the Langmuir isotherm model. Activation energy of the adsorption process (Ea) was calculated as 55.94 kJ mol−1 by using the Arrhenius equation, indicating chemisorption nature of adsorption of Crystal violet onto eggshells. A thermodynamic study showed spontaneous and exothermic nature of the adsorption process. An artificial neural network (ANN) model was developed to predict the dye removal performance of eggshells. The ANN model provided reasonable predictive performance. It was concluded that simulations based on the developed ANN model can estimate the behavior of the adsorption process under different experimental conditions.

Adsorption of lead using a new green material obtained from Portulaca plant

In the present study the potential of a new green material obtained from Portulaca oleracea plant was investigated. The material was used without any chemical treatment to study the adsorption behavior of lead ions from aqueous solution. Various batch experiments were carried out using different experimental conditions such as pH, contact time, adsorbent concentration, and metal ion concentration to identify the optimum conditions. The influence of these parameters on the adsorption capacity was studied. Results showed the optimum initial pH for adsorption as 6. Adsorption equilibrium was reached in 120 min. The adsorption data were modeled using both the Langmuir and Freundlich classical adsorption isotherms. Results show ~78% removal of lead from aqueous solution. The kinetic data corresponded well with pseudo second-order equation. From the initial results, the green material obtained from the waste of Portulaca seems to be a potential low-cost adsorbent for removal of lead ions from water.