Efficiency of chemically modified low cost adsorbents for the removal of heavy metals from waste water: a comparative study.
Environmental Engineering Laboratory, Department of Chemical Engineering, Indian Institute of Technology Madras, Chennai-600 036.
In this paper, a comparative study of removal efficiency of heavy metals [copper Cu(II), Manganese--Mn(II), Iron--Fe(II), Nickel--Ni(II), Lead--Pb(II) and Zinc--[Zn(II)] from aqueous solution by adsorption on non-conventional materials and on chemically activated non-conventional materials, is presented. It is found that the adsorption potential varies as a function of contact time, concentration, particle size, pH and flow rate. Of all the low cost adsorbents used in the study, saw dust is found to possess greater adsorption efficiency for all metals, than rice husk under identical experimental conditions. Chemically activated saw dust could remove 98.28% of Cu(II); 100% of Mn(II); 96.72% of Fe(II); 96.72% of Cd(II); 75% of Cr(VI); 80% of Ni(II); 95% of Pb(II) and 93% of Zn(II), from the corresponding metal solution taken one at a time.
School of Urban Construction, University of South China, 28 West Changsheng Road, Hengyang, Hunan 421001, PR China. firstname.lastname@example.org
Biosorption of uranium (VI) ions by immobilized Aspergillus fumigatus beads was investigated in a batch system. The influences of solution pH, biosorbent dose, U (VI) concentration, and contact time on U (VI) biosorption were studied. The results indicated that the adsorption capacity was strongly affected by the solution pH, the biosorbent dose and initial U (VI) concentration. Optimum biosorption was observed at pH 5.0, biosrobent dose (w/v) 2.5%, initial U (VI) concentration 60 mg L(-1). Biosorption equilibrium was established in 120 min. The adsorption process conformed to the Freunlich and Temkin isothermal adsorption models. The dynamic adsorption model conformed to pseudo-second order model.
Adsorption of copper (II), chromium (III), nickel (II) and lead (II) ions from aqueous solutions by meranti sawdust.
Division of Bio-resource, Paper and Coatings Technology, School of Industrial Technology, Universiti Sains Malaysia, 11800 Penang, Malaysia. email@example.com
The present study proposed the use of meranti sawdust in the removal of Cu(II), Cr(III), Ni(II) and Pb(II) ions from synthetic aqueous solutions. Batch adsorption studies showed that meranti sawdust was able to adsorb Cu(II), Cr(III), Ni(II) and Pb(II) ions from aqueous solutions in the concentration range 1-200mg/L. The adsorption was favoured with maximum adsorption at pH 6, whereas the adsorption starts at pH 1 for all metal ions. The effects of contact time, initial concentration of metal ions, adsorbent dosage and temperature have been reported. The applicability of Langmuir, Freundlich, and Dubinin-Radushkevich (D-R) isotherm was tried for the system to completely understand the adsorption isotherm processes. The adsorption kinetics tested with pseudo-first-order and pseudo-second-order models yielded high R(2) values from 0.850 to 0.932 and from 0.991 to 0.999, respectively. The meranti sawdust was found to be cost effective and has good efficiency to remove these toxic metal ions from aqueous solution.
Centre for Rural Development and Technology, Indian Institute of Technology-Delhi, Hauz Khas, New Delhi 110016, India.
Removal of hexavalent Cr from aqueous solutions by bark of Acacia nilotica L. was studied in batch process. Different parameters of adsorption viz. effect of pH, effect of dose and effect of contact time were studied. The percentage removal of Cr (VI) from synthetic sample was found to be 89.0 and 93.1% for 1.0 mm and 0.3 mm Acacia bark carbon (ABC) respectively and 60.9% and 68.1% for 1.0 mm and 0.3 mm Acacia bark untreated (ABU) respectively, in 30 min contact time. The optimum pH for both adsorbents was found to be 2.0 and adsorption equilibrium was found to be 30 min. for both adsorbents. The adsorption process was found to follow first order rate mechanism as well as Freundlich isotherm.
Other papers by authors:
Effect of loading rate and HRT on the removal of cephalosporin and their intermediates during the operation of a membrane bioreactor treating pharmaceutical wastewater.
Environmental Engineering Laboratory, Department of Civil Engineering, Pondicherry Engineering College, Puducherry 605 014, India. firstname.lastname@example.org
The viability of treating high-concentration antibiotic wastewater by a membrane bioreactor (MBR) was studied using submerged flat sheet membrane. The major problems for these modules are concentration polarization and subsequent fouling. By using gas-liquid two-phase flow, these problems can be ameliorated. A case study has been identified and the current issues in one of the major pharmaceutical industry (manufacturing cephalosporin drugs) located in Chennai, India, has been discussed for the possible removal of anaerobically transformed intermediates of antibiotic pharmaceutical wastewater. The objective of the study was to determine the effect of organic loading rate and hydraulic retention time on the removal of cephalosporin derivative, viz., cephalexin (C(16)H(17)N(3)O(4)S.H(2)O) and the intermediates [7-amino-3-deacetoxycephalosporanic acid (7-ADCA) and acyl group (Phenyl acetic acid)] in the MBR with enhanced biodegradation using bioaugmentation technique. Based on the critical examination of results, the industry is looking for the alternatives of either direct disposal of 7-ADCA and phenyl acetic acid or for further degradation and disposal, which will essentially require additional cost and maintenance. The present regulatory standard implemented at a global level,(meaning the intermediates which are transformed during its course of travel within the industry and in the treatments plants, i.e., in the present study it is, 7-ADCA and phenyl acetic acid are not allowed to discharge on water bodies), does not envisage such disposal alternatives and hence the present study was aimed at the complete removal of intermediates (7-ADCA) and phenyl acetic acid prior to discharge.
Effect of loading rate and HRT on the removal of cephalosporin and their intermediates during the operation of a membrane bioreactor treating pharmaceutical wastewater.
Environmental Engineering Division, Department of Civil Engineering, Pondicherry Engineering College, Pondicherry - 605 014, India. email@example.com
The viability of treating high-concentration antibiotic wastewater by an anaerobic membrane bioreactor was studied using submerged flat sheet membrane. The objective of the study was to determine the effect of organic loading rate and hydraulic retention time on the removal of cephalosporin derivative, viz. cephalexin, and the intermediates 7-amino-3-deacetoxycephalosporanic acid (7-ADCA) and acyl group (phenyl acetic acid) in an anaerobic membrane bioreactor with enhanced biodegradation using the bioaugmentation technique. The pharmaceutical industry is looking for alternatives to either direct disposal of 7-amino-3-deacetoxycephalosporanic acid and phenyl acetic acid, or further degradation and disposal, which will essentially require additional costs and maintenance. The present regulatory standard, implemented at a global level, does not allow for such disposal alternatives and hence the present study was aimed at the complete removal of the intermediates 7-ADCA and phenyl acetic acid prior to discharge.
Effect of inoculum-substrate ratio on acclimatization of pharmaceutical effluent in an anaerobic batch reactor.
Department of Civil Engineering, Pondicherry Engineering College, Pondicherry-605 014.
Anaerobic treatment has gained tremendous success over the past two decades for treatment of industrial effluents. Over the past 30 years, the popularity of anaerobic wastewater treatment has increased as public utilities and industries have utilized its considerable benefits. Low biomass production, row nutrient requirements and the energy production in terms of methane yield are the significant advantages over aerobic treatment process. Due to the disadvantages reported in the earlier investigations, during the past decade, anaerobic biotechnology now seems to become a stable process technology in respect of generating a high quality effluent. The objective of the present experimental study was to compare the biodegradability of recalcitrant effluent (pharmaceutical effluent) for various inoculum-substrate ratios. The batch experiments were conducted over 6 months to get effect of ratio of inoculum-substrate on the acclimatization of pharmaceutical effluent. The tests were carried out in batch reactors, serum bottles, of volume 2000 mL and plastic canes of 10000 mL. Each inoculum was filled with a cow dung, sewage and phosphate buffer. The batch was made-up of diluted cow dung at various proportions of water and cow dung, i.e., 1:1 and 1:2 (one part of cow dung and one part of water by weight for 1:1). The bottles were incubated at ambient temperature (32 degrees C-35 degrees C). The bottles were closed tightly so that the anaerobic condition is maintained. The samples were collected and biodegradability was measured once in four days. The bottles were carefully stirred before gas measurement. The substrate was added to a mixture of inoculum and phosphate nutrients. The variations in pH, conductivity, alkalinity, COD, TS, TVS, VSS, and VFA were measured for batch process. The biogas productivity was calculated for various batches of inoculum-substrate addition and conclusions were drawn for expressing the biodegradability of pharmaceutical effluent on acclimatization period and influent COD concentration.
Department of Civil Engineering, Pondicherry Engineering College, Pondicherry.
Nineteen representative water samples were collected from surface and ground water sources, covering urban, rural area, shallow and deep aquifers in Pondicherry region. The samples were analysed for various pesticide residues such as HCH, Aldrin and DDT. Both surface and ground water sources found to exhibit the residuals of various pesticides. The residual levels oforganochlorine pesticides were found to be three to four times more in ground water sources of agricultural areas than in urban areas, indicating the impact of usage of pesticides for agriculture. It is evident that total residuals of organochlorine pesticides are more in tanks followed by shallow wells and deep wells. However, the residual levels of pesticides were found well below the maximum acceptable level of 100 ng/L for individual pesticides for drinking purpose in the study area. Though the residual levels of pesticides in the study area were well below the acute toxicological problems, the major concern is for long term, chronic exposure from compounds that may be carcinogenic.
Department of Civil Engineering, Pondicherry Engineering College, Environmental Engineering Laboratory, Pondicherry 605 014, India.
The study investigates the viability of biogas generation by integrating the biodegradable waste product of sugar industry viz., pressmud with municipal sewage using biomethanation process. The total solid content of pressmud and sewage mixture was optimized with respect to maximization of biogas yield with continuous monitoring over several operating parameters. Optimum total solid content of 5% found to yield 80 m3 of biogas per ton of pressmud compared to 65m3 per ton of conventional digestion of pressmud alone. It is estimated that 3.4 x 10(8) m3 of biogas can be generated through integrated biomethanation from the potential of4.2 million tons ofpressmud available annually in India.
Department of Mechanical Engineering Indian Institute of Technology Madras Chennai 600036, India.
A Reply to the Comment by Pawel Keblinski and David G. Cahill.
Department of Microbiology, Dr ALM Postgraduate Institute of Basic Medical Sciences, University of Madras, Chennai, India. firstname.lastname@example.org
We report herein a case of primary cutaneous zygomycosis caused by Rhizopus oryzae in a 7-year-old girl with acute lymphoblastic leukemia (ALL) receiving intensive chemotherapy. The diagnosis was based on observation of hyphal elements in cutaneous biopsy and isolation of the fungus in culture. The patient responded to surgical intervention and treatment with amphotericin B.
Department of Mechanical Engineering, Indian Institute of Technology Madras, Chennai 600 036, India.
A comprehensive model has been proposed to account for the large enhancement of thermal conductivity in nanofluids and its strong temperature dependence, which the classical Maxwellian theory has been unable to explain. The dependence of thermal conductivity on particle size, concentration, and temperature has been taken care of simultaneously in our treatment. While the geometrical effect of an increase in surface area with a decrease in particle size, rationalized using a stationary particle model, accounts for the conductivity enhancement, a moving particle model developed from the Stokes-Einstein formula explains the temperature effect. Predictions from the combined model agree with the experimentally observed values of conductivity enhancement of nanofluids.
Immunogenicity and safety of 10 mg and 20 mg doses of Genevac-B, a recombinant hepatitis B vaccine, in healthy adolescents.
Anaerobic treatment and biogas recovery for sago wastewater management using a fluidized bed reactor.
Environmental Engineering Laboratory, Department of Chemical Engineering, Indian Institute of Technology, Madras.
Starch manufacturing industrial units, such as sago mills, both at medium and large scale, suffer from inadequate treatment and disposal problems due to high concentration of suspended solid content present in the effluent. In order to investigate the viability of treatment of sago effluent, a laboratory scale study was conducted. The treatment of sago effluent was studied in a continuous flow anaerobic fluidized bed reactor. The start-up of the reactor was carried out using a mixture of digested supernatant sewage sludge and cow dung slurry in different proportions. The effect of operating variables such as COD of the effluent, bed expansion, minimum fluidization velocity on efficiency of treatment and recovery of biogas was investigated. The treated wastewater was analysed for recycling and reuse to ensure an alternative for sustainable water resourse management. The maximum efficiency of treatment was found to be 82% and the nitrogen enriched digested sludge was recommended for agricultural use.
Latest similar papers:
PLoS One. 2012 ;7 (8):e43328 22927957
Fabrication of Polypyrrole/Graphene Oxide Composite Nanosheets and Their Applications for Cr(VI) Removal in Aqueous Solution.
Alan G. MacDiarmid Institute, College of Chemistry, Jilin University, Changchun, People's Republic of China.
In this paper, we report on the simple, reliable synthesis of polypyrrole (PPy)/graphene oxide (GO) composite nanosheets by using sacrificial-template polymerization method. Herein, MnO(2) nanoslices were chosen as a sacrificial-template to deposit PPy, which served as the oxidant as well. During the polymerization of pyrrole on surface of GO nanosheets, MnO(2) component was consumed incessantly. As a result, the PPy growing on the surface of GO nanosheets has the morphology just like the MnO(2) nanoslices. This method can provide the fabrication of PPy nanostructures more easily than conventional route due to its independence of removing template, which usually is a complex and tedious experimental process. The as-prepared PPy/GO composite nanosheets exhibited an enhanced properties for Cr(VI) ions removal in aqueous solution based on the synergy effect. The adsorption capacity of the PPy/GO composite nanosheets is about two times as large as that of conventional PPy nanoparticles. We believe that our findings can open a new and effective avenue to improve the adsorption performance in removing heavy metal ions from waste water.
Instituto de Química, Universidade Federal de Uberlândia, Uberlândia, MG, Brazil.
Metal contaminants are generally removed from effluents by chemical and physical processes which are often associated with disadvantages such as the use of toxic reagents, generation of toxic waste and high costs. Hence, new techniques have been developed, among them the study of natural adsorbents, for instance, the use of Moringa oleifera seeds. The potential of M. oleifera seeds for nickel removal in aqueous systems was investigated. The seeds utilized were obtained from plants grown in Uberlândia/Brazil. After being dried and pulverized, the seeds were treated with 0.1 mol/L NaOH. Fourier transform infrared spectroscopy, scanning electron microscopy and thermogravimetric analyses were used for the characterization of the material. Using the optimized methodology (50 mL of 4.0 mg/L Ni(II), pH range of 4.0-6.0, agitation time of 5 min and adsorption mass of 2.0 g) more than 90% of Ni(II) could be removed from water samples. The sorption data were fitted satisfactorily by the Langmuir adsorption model. Evaluation applying the Langmuir equation gave the monolayer sorption capacity as 29.6 mg/g. The results indicate that this material could be employed in the extraction of nickel, considering its ease of use, low cost and environmental viability, which make it highly attractive for application in developing countries.
Removal of lead(II) and copper(II) from aqueous solution using foitite from Linshou mine in Hebei, China.
College of Material Science and Engineering, Sichuan University, Chengdu 610064, China.
Foitite from Linshou mine in China's Hebei province was investigated as an adsorbent to remove Pb(II) and Cu(II) from aqueous solution. The results showed that foitite can readily remove heavy metal ions from aqueous solution. The data shows that the metal uptake for Pb(II) increases rapidly, accounting for 74.47% when contact time was 2 min. In contrast to Pb(ll), there was a worse capability for adsorption of Cu(II). In the first 4 min, the metal uptake accounted for 34.7%. According to the analytical results obtained from X-ray diffraction, laser Raman spectrum, X-ray energy dispersive spectrometer, and Zeta potential, the removal mechanism of Pb(II) and Cu(II) by using foitite can be explained as following: firstly, the existence of an electrostatic field around foitite particles can attract heavy metal ions and consequently combine heavy metal ions with OH; secondly, heavy metal ions in the solution are exchanged with the Fe3+ and Al3+ in the foitite.
Tanweer Ahmad, Mohammad Danish, Mohammad Rafatullah, Arniza Ghazali, Othman Sulaiman, Rokiah Hashim, Mohamad Nasir Mohamad Ibrahim
School of Industrial Technology, Universiti Sains Malaysia, Penang, Malaysia. email@example.com
BACKGROUND In tropical countries, the palm tree is one of the most abundant and important trees. Date palm is a principal fruit grown in many regions of the world. It is abundant, locally available and effective material that could be used as an adsorbent for the removal of different pollutants from aqueous solution. REVIEW This article presents a review on the role of date palm as adsorbents in the removal of unwanted materials such as acid and basic dyes, heavy metals, and phenolic compounds. Many studies on adsorption properties of various low cost adsorbent, such as agricultural waste and activated carbons based on agricultural waste have been reported in recent years. CONCLUSION Studies have shown that date palm-based adsorbents are the most promising adsorbents for removing unwanted materials. No previous review is available where researchers can get an overview of the adsorption capacities of date palm-based adsorbent used for the adsorption of different pollutants. This review provides the recent literature demonstrating the usefulness of date palm biomass-based adsorbents in the adsorption of various pollutants.
Laboratory of Water, Energy and Environment, National School of Engineers, University of Sfax, Sfax 1173-3038, Tunisia. firstname.lastname@example.org
Effects of impurities on the removal of heavy metals by natural limestones in aqueous solutions were studied by evaluating various factors including limestone concentration, pH, contact time and temperature. Solutions of Pb(II), Cd(II), Cu(II) and Zn(II), prepared from chloride reagents at a concentration of 10 mg/L, were studied in a batch method. Four natural limestone samples, collected from the Campanian-Maastrichtian limestone beds in Tunisia, were used as adsorbents. Sorption experiments indicated that high removal efficiencies could be achieved. Limestone samples containing impurities, such as silica, iron/aluminum oxides and different kinds of clay minerals, demonstrated enhanced sorption capacity, nearing 100% removal in some cases. Kinetic experiments showed that the sorption of metal ions occurred rapidly at a low coverage stage, and that solutions were nearly at equilibrium after 60 min. Data trends generally fit pseudo-second order kinetic, and intra-particle diffusion, models. The following conditions were found to promote optimum, or near-optimum, sorption of heavy metals: 1) contact time of more than 60 min, 2) pH = 5, 3)>3 g/L limestone concentration and 4) T = 35 °C. The results of this study suggest that the limestones from northern Tunisia, that contain higher amounts of silica and iron/aluminum oxides, are promising adsorbents for the effective removal of toxic heavy metals from wastewaters.
Cr(VI) and Cr(III) removal from aqueous solution by raw and modified lignocellulosic materials: a review.
Centro de Geociencias-Universidad Nacional Autónoma de México, Campus Juriquilla, Boulevard Juriquilla 3001, 76230 Queretaro, Mexico. email@example.com
In aqueous systems, chromium usually exists in both trivalent and hexavalent oxidation states, being Cr(VI) of particular importance and concern due to its great toxicity. Industrial sources of Cr(VI) are leather tanning, mining of chrome ore, production of steel and alloys, etc. The most common conventional method for Cr(VI) removal is reduction to Cr(III) at pH 2.0 and precipitation of Cr (OH)(3) with lime at pH 9-10. The disadvantage of precipitation is the disposal of the solid waste. Adsorption of Cr by different low cost materials seems to be a suitable choice for wastewater treatment. Many by-products of agriculture have proved to be suitable low cost adsorbents for Cr(VI) and Cr(III) removal from water. Lignocellulosic residues, which include both wood residues and agricultural residues, have adsorption capacity comparable to other natural sorbents, but they have the advantage of very low or no cost, great availability and simple operational process. This study is a review of the recent literature on the use of natural and modified lignocellulosic residues for Cr adsorption. The Cr maximum adsorption capacity and the adsorption mechanism under different experimental conditions are reported when possibly.
Central Department of Chemistry, Tribhuvan University, Kirtipur, Kathmandu, Nepal.
A new process for the xanthation of sugarcane (Saccharum officinarum) bagasse was investigated for the separation of cadmium, lead, nickel, zinc and copper from their aqueous solutions. Adsorption capacity of the charred xanthated sugarcane bagasse (CXSB) was found to be significantly more than the several biosorbents reported in the literatures. The modified material was characterized by FTIR and elemental analysis. The kinetics of sorption of the tested metals was fast, reaching equilibrium within 20-40 min. The maximum adsorption capacities evaluated in terms of mol/kg dry gel were 1.95 for Cd(II), 1.58 for Pb(II), 2.52 for Ni(II), 2.40 for Zn(II) and 2.91 for Cu(II), respectively. The high adsorption capacity and the kinetics results indicated that CXSB can be used as the selective adsorbent for the removal of these respective metal ions from wastewater.
College of Chemical Engineering, Sichuan University, Chengdu, Sichuan 610065, China.
In this study, corncobs biomass was utilized as an adsorbent to remove Pb(II) from aqueous solution. The adsorption behavior of Pb(II) was studied under different conditions, including solution pH, contact time and metal concentration. Ground corncobs were modified with CH(3)OH and NaOH to investigate the effect of chemical modification on Pb(II) binding capacity. Results showed that Pb(II) binding on the biomass is pH-dependent and the kinetics can be well described by the Lagergren-second-order model. The maximum Pb(II) binding capacity q(max) calculated from Langmuir isotherm was 0.0783 mmol/g. After base hydrolysis of the biomass, Pb(II) binding capacity increased from 0.0783 to 0.2095 mmol/g (about 43.4 mg Pb/g). However, Pb(II) binding capacity on the esterified corncobs decreased greatly from 0.0783 to 0.0381 mmol/g. Fourier transform infrared spectroscopy (FTIR) analysis showed that hydroxyl and carboxylic (COO(-)) groups on the biomass play an important role in Pb(II) binding process. The X-ray photoelectron spectroscopy (XPS) data further indicated that lead is adsorbed as Pb(2+) and is attached to oxide groups on the biomass.
Removal of heavy metals from artificial metals contaminated water samples based on micelle-templated silica modified with pyoverdin I.
Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science, Khon Kaen University, Khon Kaen 40002, Thailand. firstname.lastname@example.org
The micelle-templated silica (MTS) was firstly chemically modified with 3-glycidoxypropyl-trimethoxysilane (GPTMS) before immobilized with pyoverdin I. The characteristics of pyoverdin I-anchored onto the modified MTS were investigated using fluorescence, infrared spectra and scanning electron microscopy. The specific surface area of all materials was calculated by Brunauer, Emmett and Teller (BET) method using nitrogen isotherm adsorption data. As the results, the surface area of commercial silica gel decreased from 609.2 to 405.4 m2/g, it indicated that the pyoverdin I could be immobilized onto the surface of silica solid support. This adsorbent was used for extraction of Fe(III), Cu(II), Zn(II), and Pb(II) in artificial metals contaminated water. Experimental conditions for effective adsorption of trace levels of metal ions were optimized with respect to different experimental parameters using batch procedure. The optimum pH value for the removal of metal ions simultaneously on this adsorbent was 4.0. Complete desorption of the adsorbed metal ions from the adsorbent was carried out using 0.25 mol/L of EDTA. The effect of different cations and anions on the adsorption of these metals on adsorbent was studied and the results showed that the proposed adsorbent could be applied to the highly saline samples and the sample which contains some transition metals.
Removal of divalent heavy metals (Cd, Cu, Pb, and Zn) and arsenic(III) from aqueous solutions using scoria: kinetics and equilibria of sorption.
Department of Earth and Environmental Sciences and the Environmental Geosphere Research Lab (EGRL), Korea University, Seoul 136-701, Republic of Korea.
Kinetic and equilibrium sorption experiments were conducted on removal of divalent heavy metals (Pb(II), Cu(II), Zn(II), Cd(II)) and trivalent arsenic (As(III)) from aqueous solutions by scoria (a vesicular pyroclastic rock with basaltic composition) from Jeju Island, Korea, in order to examine its potential use as an efficient sorbent. The removal efficiencies of Pb, Cu, Zn, Cd, and As by the scoria (size=0.1-0.2mm, dose=60gL(-1)) were 94, 70, 63, 59, and 14%, respectively, after a reaction time of 24h under a sorbate concentration of 1mM and the solution pH of 5.0. A careful examination on ionic concentrations in sorption batches suggested that sorption behaviors of heavy metals onto scoria are mainly controlled by cation exchange. On the other hand, arsenic appeared to be sensitive to specific sorption onto hematite (a minor constituent of scoria). Equilibrium sorption tests indicated that the removal efficiency for heavy metals increases with increasing pH of aqueous solutions, which is resulted from precipitation as hydroxides. Similarly, multi-component systems containing heavy metals and arsenic showed that the arsenic removal increases with increasing pH of aqueous solutions, which can be attributed to coprecipitation with metal hydroxides. The empirically determined sorption kinetics were well fitted to a pseudo-second order model, while equilibrium sorption data for heavy metals and arsenic onto scoria were consistent with the Langmuir and Freundlich isotherms, respectively. Natural scoria studied in this work is an efficient sorbent for concurrent removal of divalent heavy metals and arsenic.