Removal of arsenic from simulated groundwater by GAC‐Fe: A modeling approach

Abstract

A study on kinetics and equilibrium is presented on the adsorption of arsenic species from simulated groundwater containing arsenic (As(III):As(V)::1:1), Fe and Mn in concentrations of 0.188 mg/L, 2.8 mg/L and 0.6 mg/L, respectively, by iron impregnated granular activated charcoal (GAC-Fe). Also presented is the interaction effect of As, Fe and Mn on the removal of arsenic species from water, which simulates contaminated groundwater. Among conventional models, pseudo second-order kinetic model and Freundlich isotherm were adequate to explain the kinetics and equilibrium of adsorption process, respectively. However, in comparison to conventional isotherm empirical polynomial isotherm provided a more accurate prediction on equilibrium specific uptakes of arsenic species. Effects of initial concentrations of As, Fe and Mn on the removal of total arsenic (As(T)), As(V) & As(III) have been correlated within the error limit of À0.2 to þ5.64%. V

Arsenic Removal from Water by Iron-Modified Bamboo Charcoal

“…Similar results have also been obtained in arsenic adsorption studies using iron-modified granular activated carbon (Mondal et al 2009) and some other adsorption experiments (Lazaridis and Asouhidou 2003;Senthilkumaar et al 2006). The first linear portions of the plots depict the instantaneous adsorption on the outer surface; while the second portions represent macropore diffusion, with intraparticle diffusion controlling the rate; and the third parts represent microspore/mesopore diffusion (Mondal et al 2009). The multiple nature of the relationship implies that the adsorption processes for both arsenic species were complex and controlled by intraparticle diffusion and film diffusion.…”

Removal of cadmium and copper ions by Trichosporon cutaneum R57 cells immobilized onto polyvinyl alcohol/tetraethoxysilane hybrid matrices

“…To describe heavy metal biosorption kinetics, pseudo first and second order equations as well as an intraparticle diffusion equation have been commonly applied [18][19][20][21]. However in many studies of bivalent metal ion sorption a second order kinetic model adequately described the experimental data [18][19][20].…”

Effect of pH and Treatment Time on the Removal of Arsenic Species from Simulated Groundwater by Using Fe<SUP>3+</SUP> and Ca<SUP>2+</SUP> Impregnated Granular Activated Charcoals

“…Each 50ml of the synthetic water sample containing 188µg/l As (As(III) : As(V) = 1:1), 2.8mg/l Fe and 0.6mg/l Mn was added with calculated amount of adsorbents, as optimized elsewhere [7,8] in 100ml plastic bottle. The optimum adsorbent dose was fixed to get the arsenic concentration below10µg/l from an initial concentration of 188µg/l.…”

“…However due to impregnation of metal ions the positive charge density on surface modified GACs increases as consequently arsenic removal increases. Optimum adsorbent concentrations was considered for GAC, GAC-Fe and GAC-Ca as 16g/l, 5g/l and 8g/l respectively on the basis of earlier experiments as reported elsewhere [7,8]. Thus, the amount of GAC, GAC-Fe and GAC-Ca present in 50ml solution are 0.8g, 0.25g and 0.4g respectively.…”

“…The above observations can also be explained on the basis of the migration and diffusion rates of arsenic species on the surface modified GACs. As described elsewhere [7,12] the film diffusion coefficients of As(III) and As(V) for GAC-Fe are more than that of GAC-Ca whereas pore diffusion coefficients of As(III) and As(V) for GAC-Fe are less than that of GAC-Ca. The higher value of film diffusion coefficient for GAC-Fe may be due to the more positive charge on GAC-Fe and more pore diffusion coefficient of GAC-Ca may result lower equilibrium time for GAC-Ca than GAC-Fe.…”