Comparative Study of Adsorption Capacity of Two Mixed Materials for Arsenic Remediation (original) (raw)
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2021
Arsenic pollution is one of issues for drinkable water supply in rural areas of Burkina Faso. The objective of this study was to look for a cheap technology for a better treatment of enriched arsenic water up to the admissible value (10 µg/L) in drinking water. To fulfil this objective, two mixed materials were prepared using a solid / solid mixture between laterite soil and granular ferric hydroxide for arsenic adsorption. Chemical analysis of laterite soil indicated a high amount of iron, aluminum and silicon. Batch experiments were conducted for As(V) adsorption using aqueous solutions. Results showed that the adsorption of arsenic (V) was strongly influenced by contact time, initial pH, adsorbent amount and initial As(V) concentration requiring their optimization. Indeed, the increase of the contact time between 5 and 90 min involved an increase of adsorption capacity up to 49.47µg/g while a change of initial pH caused a variation of adsorption capacity from 49 to 42.38 µg/g. An...
Development of a Treated Laterite for Arsenic Adsorption: Effects of Treatment Parameters
Industrial & Engineering Chemistry Research, 2010
A porous and efficient arsenic adsorbent (specific surface area, 181 (4 m 2 /g; pore volume, 0.35 (0.01 mL/g) is prepared from raw laterite by acid followed by alkali treatment. FTIR, XRD, SEM-EDAX, HRTEM, and a surface area analyzer are used for detailed characterization of treated materials. Adsorption of arsenic on treated laterite (TL) using arsenic spiked distilled water and contaminated groundwater (CGW) is studied in the batch and fixed-bed column modes. The Langmuir isotherm fits better to the experimental data compared to the Freundlich isotherm. The Langmuir maximum capacities of As(V) and As(III) on the best-performing treated material are found to be 24.8 (3.9 and 8.0 (1.4 mg/g, respectively. Arsenic adsorption on TL follows pseudo-second-order kinetics. The Langmuir maximum adsorptions of arsenic on raw laterite and TL using CGW as the total arsenic are found to be 0.11 (0.01 and 7.5 (0.4 mg/g, respectively. In the fixedbed column run, the 6.5 cm TL bed is capable to produce ∼3000 times the bed volume of treated water with an effluent arsenic concentration <10 µg/L using CGW as an influent. The arsenic adsorption capacity of TL is found to be 30 to 40 times higher compared to that of raw laterite.
Arsenic removal from aqueous solutions by adsorption on laterite soil
Journal of Environmental Science and Health, Part A, 2007
Hydrous iron oxide impregnated alginate beads were developed for effective arsenic removal from water. As(III) adsorption was maximized at neutral pH while As(V) adsorption was higher in acidic conditions. Adsorption efficiency for both As(III) and As(V) mostly increased with increasing iron loading, but As(V) adsorption slightly decreased at high iron loading. Phosphate showed a pronounced interfering effect, especially at high concentration. Kinetics data fitted to pseudo-second-order and intraparticle diffusion model suggested chemisorption and intra-particle diffusion might mainly govern As(III) and As(V) adsorption, respectively. Beads were regenerated using NaOH solution and successfully reused for multiple cycles.
Arsenic removal from real-life groundwater by adsorption on laterite soil
Journal of Hazardous Materials, 2008
The adsorption characteristics of arsenic on laterite soil, a low-cost natural adsorbent, were studied in the laboratory scale using real-life sample. The studies were conducted by both batch and continuous mode. Laterite soil was found to be an efficient adsorbent for arsenic removal from the groundwater collected from arsenic affected area. The initial concentration of arsenic in the sample was 0.33 ppm. Under optimized conditions the laterite soil could remove up to 98% of total arsenic. The optimum adsorbent dose was 20 g/l and the equilibrium time was 30 min. Isotherm studies showed that the process is favorable and spontaneous. The kinetics showed that the removal of arsenic by laterite soil is a pseudo-second-order reaction. In the column study the flow rate was maintained at 1.49 m 3 /(m 2 h). Using 10 cm column depth, the breakthrough and exhaust time found were 6.75 h and 19.0 h, respectively. Height of adsorption zone was 9.85 cm, the rate at which the adsorption zone was moving through the bed was 0.80 cm/h, and the percentage of the total column saturated at breakthrough was 47.12%. The value of adsorption rate coefficient (K) and the adsorption capacity coefficient (N) were 1.21 l/(mg h) and 69.22 mg/l, respectively. Aqueous NaOH (1 M) could regenerate the adsorbent, and the regenerated adsorbent showed higher efficiency.
Radiochimica Acta, 2014
The sorption behavior of arsenic on minerals from a lateritic weathering has been investigated to evaluate its potential for the decontamination of arsenic ions from aqueous media. Various physicochemical parameters such as pH, equilibration time, adsorbent dose, concentration of adsorbate, effect of diverse ions and temperature were studied in order to simulate the best conditions under which this material can be used as an adsorbent, employing batch method and radiotracer technique. Maximum adsorption was observed in buffer solutions having pH of 2.0 and 8–9, using 0.5 g of adsorbent for 6.674 · 10 –5 mol L –1 arsenic concentration in 10 min equilibration time. The sorption data followed the pseudo-second order reaction kinetics. The adsorption data fit both the Freundlich and Dubinin-Radushkevich isotherm equations over the range of 3.195 · 10 –5 to 3.195 · 10 –3 mol L –1 arsenic concentration. The characteristic Freundlich constants i.e. 1/n = 0.427 ± 0.009 and K = 3.04 × 10−4 ±...
Removal of arsenic from water by different adsorbents
Indian Journal of Chemical Technology, 2004
Present study is carried out for the removal of As(III) from water using commonly available adsorbents such as sand, from Yamuna river ( Delhi ), as well as from Ganga river (Kolkata), activated carbon, Hametite ore and sand -iron scrap mixture. All these adsorbents are used as received but sand and activated carbon which do not show much adsorption for As(III) are modified by treating with different metal ions in order to improve their adsorption efficiency. Results of the laboratory experiments under static conditions have confirmed that iron impregnated granular activated carbon (GAC), spherical activated carbon (SAC) as well as sand - iron scrap mixture have much promise as a medium for the removal of As(III) in drinking water. Various parameters like adsorbent dose, contact time, pH and arsenic concentration are optimized. A simple and economical domestic arsenic removal kit has been designed and successfully evaluated in the laboratory using sand-iron scrap mixture as media fo...
Chemical Engineering Journal, 2010
An efficient porous adsorbent for arsenic is developed from abundantly available laterite using an optimized acid followed by base treatment methodology. XRD, HRTEM, surface area analyzer and FTIR are used to characterize the treated laterite (TL). Arsenic adsorption capacity of TL is evaluated under varying process conditions in batch mode using synthetic solution of single arsenic species, mixture of both As(III) and As(V) species and real arsenic contaminated groundwater (CGW). The effects of competitive ions like phosphate, silicate, carbonate, etc., on arsenic adsorption using TL are explored in details. Langmuir isotherm is found to be a better fit of the experimental isotherm data of arsenic/TL system. The Langmuir maximum adsorption capacity and constant related to adsorption energy for As(V) and As(III) on TL are found to be 21.6 ± 0.8 mg/g, 20.6 ± 0.5 L/mg and 9.4 ± 0.4 mg/g, 5.0 ± 0.1 L/mg, respectively. The competitive adsorption kinetics of individual arsenic species on TL using mixed arsenic spiked water and CGW are studied by speciation technique. Shrinking core model is applied to match the predicted bulk concentration profile of arsenic with experimental data. The model is applied to evaluate the effective pore diffusivity (D e ) and external mass transfer coefficient (K f ) of arsenic for arsenic/TL system and these values are in the range of 1.3-1.6 × 10 −9 m 2 /s and 0.076-11.25 × 10 −4 m/s, respectively. Fixed bed column runs using 6.5 cm TL bed (empty bed contact time: 2.92 min) is capable to produce ∼3000 bed volume (96.7 L, 1 bed volume = 32.23 mL) of water for effluent concentration at <10 g/L (initial arsenic concentration in CGW: 385 ± 25 g/L). The study reveals that TL is porous and highly efficient adsorbent for both arsenic species.
Laterite, Sandstone and Shale as Adsorbents for the Removal of Arsenic from Water
American Journal of Analytical Chemistry
This study aims at exploring arsenite (As (III)) removal from water using naturally available rocks (laterite, sandstone and shale) in Côte d'Ivoire. The study focused on the adsorbent dose, operating pH, contact time, initial arsenite concentration, and modelisation on the removal of arsenite by performing batch adsorption experiment with well water. The optimal dosage related to an initial As (III) concentration of 5 mg/L was about 50, 75 and 145 g/L for laterite, sandstone and shale respectively. Laterite has a better adsorption capacity in comparison to sandstone and shale. On the other hand, kinetic study reveals that the equilibrium times are 5 h for laterite, 3 h for sandstone and 8 h for shale. Results showed that laterite, sandstone and shale could remove the arsenic in groundwater at initial arsenic concentrations below 5 mg/L, satisfying the World Health Organization (WHO) standard for drinking water. Moreover, kinetics study showed that the overall adsorption rate of arsenite was described by the pseudo-second-order kinetic model.
REMOVAL OF ARSENIC FROM SYNTHETIC WASTE WATER USING ADSORPTION PROCESS
Environmental pollution particularly from heavy metals and minerals in the waste water is the most serious problem in India. Arsenic is viewed as being synonymous with toxicity. Dangerous arsenic concentration in natural water is now a worldwide problem. Existing overviews of arsenic removal technology that has traditionally been used: Adsorption. Adsorption process being very simple, economical effective and versatile has become the most preferred methods for removal of toxic contaminants from wastewater. In this project we use the iron acetate coated activated alumina (IACAA) and activated alumina (AA) as a adsorbents. The adsorption potential of IACAA for removal of arsenic [As (III)] as arsenite by batch sorption technique gives more effective results in comparision to AA. Percentage adsorption on IACAA and AA were determined as a function of contact time and adsorption dose. IACAA was characterized by EDAX (energy dispersive x-rays analysis) and SEM (scanning electron microscope). The impact of the amount of impregnated iron acetate in activated alumina on arsenic adsorption capacities was investigated in this study. In this study we also described the preparation of iron acetate and coating of iron acetate on activated alumina.