Adsorption of cadmium (II) from simulated wastewater using <i>Albizia saman</i> pod activated carbon in fixed bed columns

Abstract

The possibility of using Albizia saman pod activated carbon (ASPAC) as an adsorbent in fixed down flow adsorption columns to remove Cd (II) from wastewater was investigated for the purpose of converting the waste to a valuable product. The effects of impregnation ratio, particle size, carbon height, pressure head and initial cadmium Cd (II) concentration on the adsorption of Cd (II) from wastewater were investigated. The obtained adsorption data from the experiment was then fitted into the Hutchin's bed depth service time (BDST) model to study the columns performance at 15% and 90% breakthrough concentrations. The BDST model constants were determined. An optimal pressure head of 5 cm, impregnation ratio of 1:6, packing height of 3.5 cm, particle size of 75 µm and initial Cd (II) concentration of 0.029 mg/L were found to be the most effective combination, which removed 100 % of the Cd (II) within a service time of 14 hrs. There was a gradual decrease in the percentage of adsorbed Cd (II) with time; the percentage adsorbed became zero at 44, 56 and 86 hours respectively for 2.5 cm, 3 cm and 3.5 cm carbon heights. The breakthrough curves for Cd (II) adsorption maintained the characteristic S-curve for most dynamic studies. Chisquared test performed on the developed BDST models revealed the goodness of fit of the models for the prediction of the columns performance at all breakthrough concentrations investigated. The use of ASPAC as adsorbent for the removal of Cd (II) from wastewater in adsorption columns is therefore recommended.

Phytoremediation of emulsion paint wastewater using Azolla Pinnata, Eichhornia Crassipes and Lemna Minor

“…There are many physical, chemical and thermal methods that have been studied for the treatments of industrial paint wastewater , such as precipitation, adsorption, ion exchange, membrane filtration, evaporation, nanofiltration, using agricultural wastages, reverse osmosis, distillation, coagulation-flocculation, advanced oxidation processes such as ozone, photochemical, Fenton's, electrochemical, and using biological compounds etc. [1][2][3][4][5][6][7][8][9]. The enormous costs, adverse effects on the environment and low efficiencies associated with these remediation techniques present limitations to their availability and usage [1,3,7,8].…”

“…Compared to all the removal process phytoremediation is more efficient and cost effective. It takes more time for the removal of contaminants, but the removal is the permanent solution compared with other methods [6]. Unlike humans, plants are having capacity to detoxify heavy metals and it is done through several mechanisms such as organic acids, root reductases, phytochelatins, metallothioneines, mycorrhizae and heat shock proteins [6].…”

“…It takes more time for the removal of contaminants, but the removal is the permanent solution compared with other methods [6]. Unlike humans, plants are having capacity to detoxify heavy metals and it is done through several mechanisms such as organic acids, root reductases, phytochelatins, metallothioneines, mycorrhizae and heat shock proteins [6]. The use of plants in phytoremediation is gaining support as plants have intrinsic abilities to extract and metabolize contaminants and their cooperation with soil microorganisms and endophyte microbes that live inside plants may enhance the removal of contaminants from the environment hence the three major advantages of phytoremediation include low cost, possible in situ remediation and less impact on the environment [2,3].…”

“…There have been numerous studies on the capacities of free-floating macrophytes (i.e., Eichhornia crassipes, Lemna minor, and Spirodela polyrrhiza) for removing heavy metals from water [5]. Phytoremediation is the best alternative for tidying up condition, as it is the naturally economical and ecologically practical innovation [6]. Hence, this study was carried out to investigate the use of some selected Nigerian aquatic macrophytes namely: Azolla pinnata (Feathered mosquito fern), Eichhornia crassipes (Water hyacinth) and Lemna minor (Duck weed) for the phytoremediation of paint wastewater, to compare the efficiency of the three selected plants in phytoremediation of paint wastewater, and so minimizing the environmental hazard associated with the discharge of this wastewater onto lands and surface water bodies.…”

Performance evaluation of zirconium silicate composite for removal of cadmium and zinc ions

“…Cadmium is a markedly toxic metal and has a very low biocidal dose for mammals, which could damage the lungs, liver, and kidney [2]. Therefore, the capture of cadmium from the water source is substantial to the environment clean from pollution and human health [3]. Zinc has several radioisotopes, including 65 Zn (tl/2≈ 244.2 days), it is widely employed in agricultural, medical, and biomedical research; it is also utilized for industrial purposes [4].…”