Arsenic mitigation by chitosan-based porous magnesia-impregnated alumina: performance evaluation in continuous packed bed column

Abstract

Dissolved arsenic in contaminated groundwater is a major concern on a global scale due to its extreme toxicity. This paper reports a magnesium oxide-impregnated mesoporous alumina synthesized using biopolymer chitosan template. The adsorbent was first characterized by BET, SEM and EDAX analysis. The packed column performed effectively over wide range of pH and exhibited a maximum adsorption capacity of 17.2 mg/g for an input arsenic concentration of 20 mg/L. The experimental data fitted well with pseudo-second-order kinetics. Thermodynamic study on the adsorption phenomena revealed that arsenic adsorption on the porous adsorbent was spontaneous, and the process was exothermic. The arsenic sorption capacity at breakthrough point was greatly dependent on bed depth. A bed depth service time approach was adopted to describe the continuous flow system. The column after exhaustion was regenerated by eluting the bound arsenate [As(V)] with *15 bed volume sodium hydroxide solution. The adsorbent could retain its capacity up to five cycles of such regeneration. The influence of different operating conditions such as bed depth, flow rate and initial arsenic concentration was investigated statistically by the two-level full-factorial experimental designs to evaluate optimum operating conditions. Graphical abstract

Applications of Chitin and Chitosan in Industry and Medical Science: A Review

“…Chitosan N-benzyl sulphonate derivatives are used as sorbents for the removal of metal ions in acidic medium and chitosan can also be used to remove the color from dye house effluents as reported by Weltroswki et al (1996). Chitin and chitosan are also found to be used effectively to remove arsenic from contaminated drinking water as well as to remove petroleum products from waste water (Saha & Sarkar 2013).…”

Adsorption of Phenol from Aqueous Solution Using Lantana camara, Forest Waste: Packed Bed Studies and Prediction of Breakthrough Curves

“…The sorption capacity N o and the rate constant K a are determined from the slope and the intercept of the linear plot (Gokhale et al 2009). The model parameters can be helpful to predict the service time for other operating conditions without further experimental studies and analysis (Prakash Kumar et al 2005;Hadi et al 2011;Saha and Sarkar 2015). The model was also used to evaluate the design parameters for changed flow rate and initial concentration.…”

Electrochemical Column Cell for Continuous Oxidative Inactivation of Pathogens and Reductive Removal of Toxic Heavy Metals

“…The residence time for water flow under the solar-assisted negative potential of −3 V increased three times, and the rate of deposition of HMs increased. Further, the steepness of the breakthrough curve decreased with increasing cell number, which indicated a broadened mass transfer zone . Similarly, the deposition potential was varied from −0.5 to −5 V (solar-assisted) with fixed parameters for the electrode distance (1 cm), initial concentration (0.5 mg L –1 ), and flow rate (10 mL min –1 ).…”

“…Further, the steepness of the breakthrough curve decreased with increasing cell number, which indicated a broadened mass transfer zone. 61 Similarly, the deposition potential was varied from −0.5 to −5 V (solar-assisted) with fixed parameters for the electrode distance (1 cm), initial concentration (0.5 mg L −1 ), and flow rate (10 mL min −1 ). The optimum potential was found to be −3 V at a 1 cm distance between two electrodes for best HM remediation (Figure S13).…”