As(III) and As(V) removal from the aqueous phase via adsorption onto acid mine drainage sludge (AMDS) alginate beads and goethite alginate beads (original) (raw)
Related papers
Adsorption of As(III), Pb(II), and Zn(II) from Wastewater by Sodium Alginate Modified Materials
Journal of Analytical Methods in Chemistry, 2021
Sodium alginate (SA), polyvinyl oxide (PEO), and ceramic nanomaterials were used to prepare alginate composite gel. The present study examined the removal rate and adsorption capacity of alginate composite gel for removal of wastewater As(III), Pb(II), and Zn(II). Batch experiments were conducted to study the influence of experimental parameters such as pH and temperature, as well as the mechanism of As(III), Pb(II), and Zn(II) adsorption with the new adsorbent. The results showed the high efficiency of sodium alginate composite gel for removal of wastewater As(III), Pb(II), and Zn(II). Under the condition of the best liquid-solid ratio and the contact time, the removal rates of As(III), Pb(II), and Zn(II) were 67.42%, 95.31%, and 93.96%, respectively. The pseudo-second-order kinetic equation was superior to fit the adsorption kinetics process. The isothermal adsorption models of As(III) and Pb(II) fitted well with the Freundlich model, and Zn(II) fitted well with the Langmuir model...
Water, Air, & Soil Pollution, 2019
Arsenic (As) is considered as one of the most hazardous elements found in the groundwater. It is present in water in both arsenate (As(V)) and arsenite (As(III)) forms. On exposure for a considerable length of time to water having As concentration above the maximum permissible limit of 10 μg/L, there is a serious threat of developing various health problems including cancer. There is frequent reporting about the development of different newer methods for the removal of arsenic from water. In this present approach, a low-cost product namely modified paddy husk ash (PHA) was used as an adsorbent for the adsorption of arsenic from water. The adsorbent is important from the point of its easy availability in the tropical paddy producing countries. For improved removal efficiency and disposal of spent adsorbent, the surface of the PHA was activated with an aluminum oligomeric solution called as hydroxyl-alumina. To understand the process, various techniques such as XRD, SEM-EDS, particle size determination, and zeta potential measurements were used and the effects like variation of adsorbent dose, pH, initial arsenic concentration, and contact time were studied. The Freundlich adsorption isotherm and pseudosecond-order kinetic models were found to be the best fitted adsorption isotherm and kinetic data models respectively thereby confirming the adsorption as a multilayer chemisorption process. Finally, the issue of disposal of the spent sludge through the successful formation of cement clinkers was studied.
Acta chimica Slovenica, 2021
In the present study, brick kiln slag (BKS) has been utilized for low concentration As(III) adsorption in batch mode. BKS was modified with H2SO4 (SA) and NaOH (SB) for enhancing As(III) uptake capacity. Maximum adsorption capacity (13.7 mg/g) was observed for SA at 298 K, pH = 7.0, adsorbent dose = 0.3 g and time = 70 min which was 1.4 times higher than that of SB. Adsorption data modelled into Freundlich isotherm and pseudo-second-order kinetics. Mass transfer coefficients decreased with increase in As(III) concentration. Film diffusion significantly dominated the adsorption of As(III) ions irrespective of the initial concentration. Dimensionless Sherwood number (Sh) interrelated As(III) concentration (Co) as: Sh = 2.97(Co)-0.376, Sh = 4.12(Co)-0.215, Sh = 4.83(Co)-0.588 for H2SO4 modified, NaOH modified and native slag respectively. Low temperature (298 K) favoured As(III) adsorption (based on ∆G° value). Therefore, the modified slag can be used as an effective adsorbent for As(I...
Environmental Science and Pollution Research, 2016
Water treatment residuals (WTRs) produced in large quantities during deironing and demanganization of infiltration water, due to high content of iron and manganese oxides, exhibit excellent sorptive properties toward arsenate and arsenite. Nonetheless, since they consist of microparticles, their practical use as an adsorbent is limited by difficulties with separation from treated solutions. The aim of this study was entrapment of chemically pretreated WTR into calcium alginate polymer and examination of sorptive properties of the obtained composite sorbent toward As(III) and As(V). Different products were formed varying in WTR content as well as in density of alginate matrix. In order to determine the key parameters of the adsorption process, both equilibrium and kinetic studies were conducted. The best properties were exhibited by a sorbent containing 5 % residuals, formed in alginate solution with a concentration of 1 %. In slightly acidic conditions (pH 4.5), its maximum sorption capacity was 3.4 and 2.9 mg g −1 for As(III) and As(V), respectively. At neutral pH, the adsorption effectiveness decreased to 3.3 mg As g −1 for arsenites and to 0.7 mg As g −1 for arsenates. The presence of carboxylic groups in polymer chains impeded in neutral conditions the diffusion of anions into sorbent beads; therefore, the main rate-limiting step of the adsorption, mainly in the case of arsenates, was intraparticle diffusion. The optimal condition for simultaneous removal of arsenates and arsenites from water by means of the obtained composite sorbent is slightly acidic pH, ensuring similar adsorption effectiveness for both arsenic species.
Arabian Journal of Chemistry, 2017
A solid waste material containing Fe(III) and other metal (hydr)oxides produced in a metal surface treatment industry has been investigated for As(V) removal. In order to facilitate sorbent application, 2% of raw material has been entrapped in calcium alginate gel matrix (2% O-CA). An accurate characterization of the sorption on gel beads was undertaken, considering thermodynamic and kinetic aspects. All experiments were carried out at pH 8, since the maximum As(V) sorption was reached between pH 6 and 9. About isotherms, the best fit was obtained considering the Langmuir model and a capacity of 1.9 mg/g was achieved. The kinetic profiles evidenced that a quantitative sorption was obtained within 10 h. The 2% O-CA beads were also tested for continuous As(V) removal in a fixed bed column. Experiments were performed at constant flow rate, and varying the inlet As(V) concentration. With a view to design an automatic system for As(V) analysis in the outlet flow, the suitability of applying Anodic Stripping Voltammetry was evaluated: the method resulted appropriated to follow the As(V) content in the outlet solutions of columns with metal inlet concentration <1 mg/L. These results suggested that 2% O-CA beads could be a promising sorbent candidate for As(V) removal.
Arsenic (V) Removal by an Adsorbent Material Derived from Acid Mine Drainage Sludge
Applied Sciences, 2020
Arsenic is a toxic element that is often found in drinking water in developing countries in Asia, while arsenic poisoning is a serious worldwide human health concern. The objective of this work is to remove arsenic (V) (As(V)) from water by using an adsorbent material prepared from mine waste, called MIRESORBTM, which contains Fe, Al. The performance of the MIRESORBTM adsorbent was compared with granular ferric hydroxide (GFH), which is a commercial adsorbent. Adsorbents were characterized by using scanning electron microscopy (SEM), X-ray fluorescence spectroscopy (XRF), X-ray diffractometry (XRD), and N2 sorption with Brunauer–Emmett–Teller (BET) analysis. The kinetics, isotherms, and pH-dependency of arsenic adsorption were interrogated to gain insights into arsenic adsorption processes. The maximum adsorption capacity of MIRESORBTM was 50.38 mg/g, which was higher than that of GFH (29.07 mg/g). Moreover, a continuous column test that used environmental samples of acid mine drain...
Arsenic removal by a waste metal (hydr)oxide entrapped into calcium alginate beads
Journal of Hazardous Materials, 2009
In this work, a solid waste material from an electroplating industrial plant has been investigated for As(III) and As(V) sorption. This sorbent, a mixture of mainly Fe(III) and Ni(II) (hydr)oxides, has been used both in its native form and entrapped in calcium alginate. The effect of sorbent concentration in the gel bead, solution pH, contact time and As(III) and As(V) concentration on sorption has been studied. Furthermore the effect of the gel matrix has been investigated. A 10% (w/v) of (hydr)oxide in the gel beads was found to provide both spherical beads shape and good sorption performance. Solution pH was found to exert a stronger influence in As(V) than in As(III) sorption. The optimum pH range resulted to be within 5-10 for As(III) and within 6-9 for As(V). Taking into account these results, pH 8 was chosen for further sorption experiments. Equilibrium was reached after 48 h contact time for the studied systems. Kinetics data of both As(III) and As(V) onto native (hydr)oxide (O) and entrapped in calcium alginate beads (10% O-CA) were successfully modelled according to pseudo-first and pseudo-second order equations. Sorption equilibrium data were evaluated by the Langmuir isotherm model and the maximum capacity q max were 77.4 and 126.5 mg g −1 for As(III) on O and 10% O-CA, and 26.8 and 41.6 mg g −1 for As(V) on O and 10% O-CA, respectively. The entrapment of the (hydr)oxide in a calcium alginate gel matrix improved the As(III) and As(V) sorption by 60%.
Cyclical Cadmium Adsorption and Desorption by Activated Sludge Immobilized on Alginate Carriers
This paper concerns cadmium desorption in subsequent cycles of adsorption/desorption by chemical sorbents such as 2% sodium alginate, sodium alginate with the addition of poly(vinyl) alcohol (PVA) in the following proportions: 1.5% alginate and 0.5% PVA, 2% alginate and 2% PVA, 2% alginate and 5% PVA, and two kinds of activated sludge immobilized on alginate sorbents. It was proved that adsorption by alginate and alginate with PVA obeys a second-order rate law. The higher the PVA amount in alginate, the lower the reaction rate. Mineral acids such as hydrochloric and sulphuric acids were used as desorption agents. It was observed that all sorbents tested remove cadmium with high and almost constant efficiency from the solution con- taining 50 mgCd/dm 3 , whereas desorption effectiveness depended on the kind of sorbents and desorbing agents.
Adsorption of As(III) Ions onto Iron-containing Waste Sludge
Adsorption Science & Technology, 2010
The adsorption performance of a low-cost adsorbent (IS), viz. an iron-containing waste sludge arising during a hot-dip galvanizing process, towards the removal of As(III) ions from synthetic aqueous solutions and natural underground water was examined. The adsorption process was best described by the pseudo-second-order kinetic equation. The equilibrium adsorption data were well described by the Langmuir model. The value of the dimensional separation factor, R L , indicated favourable adsorption. The maximum adsorption capacity of IS was 625 µg As(III)/g. The variation in the extent of adsorption with temperature was used to evaluate the thermodynamic parameters for the adsorption process. The values of ∆H 0 and ∆G 0 obtained demonstrated that the adsorption process was exothermic and spontaneous. The studied material exhibited an excellent As(III) ion adsorption performance from both synthetic solutions and a natural water sample. Moreover, no secondary contaminated substances arise if the exhausted adsorbent is recycled (e.g. in glass applications).