Magnetic Ion Exchange Research Articles

Preparation and use of magnetic poly(glycidyl methacrylate) resin in drinking water treatment

AbstractMagnetic poly(glycidyl methacrylate) (m‐PGMA) was synthesized and characterized, and its efficiency in removing natural organic matter (NOM) and carbamazepine (CBZ) from synthetic water was studied. The effects of factors such as time and m‐PGMA dosage on NOM removal were investigated. Furthermore, magnetic ion exchange resin (MIEX®) was used for comparison with m‐PGMA in CBZ removal. m‐PGMA was found to have a strong magnetic character whose specific saturation magnetization and mass fraction of magnetite were 10.79 emu g−1 and 6.166 wt %, respectively, thus providing additional utility for m‐PGMA in slurry form in completely mixed continuous‐flow reactors. Lab‐scale studies showed that the removal rate rose rapidly with time and reached a pseudo‐equilibrium after 30 min. In addition, the highest doses of m‐PGMA achieved the highest removal efficiency. After 30 min of contact with 5, 10, and 15 mL L−1 of m‐PGMA, the removal rates, based on UV absorbance measurements at 254 nm (UV254), were 56%, 67%, and 79%, respectively, whereas the removal rates of dissolved organic carbon (DOC) were 53%, 60%, and 72%, respectively. Additionally, the scale ultraviolet absorbance values (SUVA) decreased during a 30 min contact time, thereby suggesting that the NOM removed by m‐PGMA had greater aromatic character. In multiple‐loading tests, UV254 removal gradually decreased and achieved 18.39% at 1600 bed volume; it was kept constant at this level. Compared to MIEX®, m‐PGMA had a higher CBZ removal rate (27.8% and 34.7% for 20 mL L−1 and 25 mL L−1 of m‐PGMA, corresponding to the removal of 200 μg L−1 CBZ). The resulting higher removal rate of CBZ contributed to stronger adsorption, a higher specific surface area, and larger pore volume. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

MIEX® and PAC for removal of hydrophilic DBP precursors

The objective of this research was to investigate promising materials for potential reduction of disinfection by‐product (DBP) formation resulting from reactions with hydrophilic natural organic matter (NOM), a source of precursors that is difficult to remove with conventional drinking water treatment process units. DBP reduction in other reported research was attributable to greater removal of hydrophobic fractions of NOM. Two nonionic resins were used to fractionate NOM before and after treatment with magnetic ion exchange (MIEX®) and a powdered activated carbon. At the chosen doses of treatment materials, bulk NOM removal remained the same (< 10% difference in dissolved organic carbon after treatment with activated carbon versus MIEX); compared with the powdered activated carbon, however, MIEX provided greater reduction of trihalomethane and haloacetic acid formation potential resulting from reactions with hydrophilic NOM. Therefore, MIEX preferentially removed hydrophilic DBP precursors. Similar results were observed for the transphilic fraction, whereas differences in the hydrophobic fraction were minimal. This research has implications for treatment facilities with elevated levels of highly reactive hydrophilic NOM in their influents and highlights the importance of source water chemistry in the selection of DBP mitigation strategies.

Competitive removal of DOM and bromide in raw waters by MIEX and iron coagulation

Dissolved organic matter (DOM) and bromide as principal precursors to halogenated disinfection byproducts (DBPs) have potential risks on the safety of drinking water after disinfection. Removal of DOM and bromide in raw water from two different waterworks using magnetic ion exchange resin (MIEX), ferric coagulation and their combination was investigated. Results showed that as MIEX dose increased, DOM and bromide coexisting in raw water could be removed effectively. DOM tended to be mainly removed by MIEX at low dose (<4 mL/L), regardless of the bromide concentration. Bromide could compete for exchange sites with DOM at high MIEX dosage (>4 mL/L). The fluorescence spectra and high performance size-exclusion chromatogram analysis indicated that at low MIEX dosage, bromide decreased the removal of low molecular weight (MW), soluble microbial byproduct-like and aromatic protein-like organic matters, which had lower affinity with MIEX in raw water. The removal of high MW humic acid, which presented greater affinity with MIEX, was not influenced at low MIEX dose but decreased at high MIEX dose with the addition of bromide. The combination of MIEX and ferric coagulation significantly enhanced the removal of DOM and reduced the requisite ferric dose by at least 67% compared to coagulation alone.

The control of N-DBP and C-DBP precursors with MIEX®

The objective of this study was to examine the potential of Magnetic Ion Exchange (MIEX®) technology for removing nitrogenous disinfection byproduct (N-DBP) precursors while minimizing carbonaceous DBP (C-DBP) precursors in (i) surface waters, and (ii) effluent impacted waters. Samples were collected from several drinking water source waters and wastewater treatment plant effluents. The effluent impacted source waters were simulated in the laboratory by mixing treated wastewater effluents with the same source water. Formation potential (FP) tests were conducted for regulated trihalomethanes (THMs), haloacetic acids (HAAs), and selected N-DBPs (nitrosamines and halonitromethanes (HNMs)) before and after the MIEX® treatment. The MIEX® process substantially lowered UV absorbance, total organic carbon, and THM and HAA FPs in all examined water samples, ranging from 39 to 87% reduction. A relatively small portion (9–33%) of HNM precursors was removed by the MIEX® treatment. On the other hand, an increase in N-nitrosodimethylamine (NDMA) FP was observed after the MIEX® process but only for the effluent impacted waters. Soluble metals, inorganic nitrogen, and bromide in effluent impacted waters did not correlate with the increase in NDMA FP. There was no effect of MIEX® treatment on the removal of other nitrosamine species precursors. Simulations of typical water treatment and distribution systems scenarios showed that NDMA concentrations remained below 10 ng/L, when chlorine alone or 40 min chlorine contact time prior to ammonia addition were employed for post-disinfection. However, when chlorine and ammonia were added simultaneously, NDMA concentration reached 36 ng/L for the water tested in the study.

Effect of magnetic ion exchange and ozonation on disinfection by-product formation

The purpose of this research was to investigate the performance of treatment with magnetic ion exchange (MIEX) resin followed by ozonation in achieving disinfection goals while controlling bromate and chlorinated disinfection by-product (DBP) formation. Three water samples were collected from raw water supplies impacted by the San Francisco Bay Delta to represent the varying levels of bromide and total organic carbon (TOC) that occur throughout the year. A fourth water was prepared by spiking bromide into a portion of one of the samples. Samples of each water were pre-treated with alum or virgin MIEX resin, and the raw and treated waters were subsequently ozonated under semi-batch conditions to assess the impact of treatment on ozone demand, ozone exposure for disinfection (“CT”), and bromate formation. Finally, aliquots of raw, coagulated, resin-treated, and ozonated waters were chlorinated in order to measure trihalomethane formation potential (THMFP). In the waters studied, MIEX resin removed 41–68% of raw water TOC, compared to 12–44% for alum. MIEX resin also reduced the bromide concentration by 20–50%. The removal of TOC by alum and MIEX resin significantly reduced the ozone demand of all waters studied, resulting in higher dissolved ozone concentrations and CT values for a given amount of ozone transferred into solution. For a given level of disinfection (CT), the amount of bromate produced by ozonation of MIEX-treated waters was similar to or slightly less than that of raw water and significantly less than that of alum-treated water. MIEX resin removed 39–85% of THMFP compared to 16–56% removal by alum. Ozonation reduced THMFP by 35–45% in all cases. This work indicates that in bromide-rich waters in which ozone disinfection is used, MIEX resin is a more appropriate treatment than alum for the removal of organic carbon, as it achieves superior TOC and THM precursor removal and decreases the production of bromate from ozone.

Evaluation of temperature impacts on drinking water treatment efficacy of magnetic ion exchange and enhanced coagulation

Magnetic ion exchange (MIEX ® ) is an emerging technology for disinfection by-product (DBP) precursor removal in the drinking water industry. Although recent research has demonstrated that this technology is capable of achieving excellent natural organic matter (NOM) removal, there is paucity of published research showing the efficacy of ion exchange (IX) technology in cold water conditions. The overall objective of this research was to evaluate at bench-scale the potential impact of cold water operating conditions on enhanced coagulation with alum, MIEX ® and a combination of MIEX® and low dose alum. All three treatments were evaluated at 1 and 20 °C with settled water quality compared in terms of turbidity, UV254, dissolved organic carbon (DOC), specific UV absorbance (SUVA), trihalomethane formation potential (THMFP) and haloacetic acid formation potential (HAAFP). The results of the study showed that all three technologies evaluated were significantly impacted by cold water operating conditions in terms of turbidity removal, and UV254 removal was significantly reduced in both the MIEX ® and MIEX ® -Alum processes. However, treatment of the surface water with the combined process resulted in the highest removal of DBP precursor material and lowest THMFP and HAAFP concentrations at both temperatures compared to the individual unit operations.

Applicability of ion exchange for NOM removal from a sulfate-rich surface water incorporating full reuse of the brine

The raw water of water treatment works ‘the Blankaart’ (Belgium) is characterized by high levels of NOM (Natural Organic Matter), alkalinity and sulfate. From 2006 until present, the possibility of applying fluidized ion exchange for NOM removal has been investigated at the plant. Pilot testing using Miex® (Magnetic Ion Exchange) resin demonstrated that under standard operating conditions, a TOC (Total Organic Carbon) removal efficiency of 40 to 50% can be achieved. Moreover, jar tests demonstrated that the application of ion exchange as a pretreatment for enhanced coagulation would allow the coagulant dose to be reduced by 60% without compromising effluent quality. Finally, column experiments were conducted to evaluate (i) the effect of full brine reuse and (ii) the possibility of using less expensive conventional ion exchange resins instead of the patented Miex® resin. Recuperation of the waste brine after flocculation with a ferric salt and dewatering was found to have no significant impact on the NOM removal efficiency. Column experiments with Miex® and conventional type 1 anion exchange resins revealed that the fluidization characteristics of both types of resin allow use in fluidized bed systems and that with both types of resin, similar NOM removal efficiencies can be attained. However, higher contact times are required when conventional resins are applied.

Mechanisms of Membrane Fouling Control by Integrated Magnetic Ion Exchange and Coagulation

Colloidal natural organic matter (NOM) is an important foulant to low-pressure membranes (LPMs) employed in drinking water treatment. Removal of colloidal NOM by magnetic ion exchange (MIEX), coagulation, and integrated MIEX and coagulation was investigated in this study to determine the relationship between colloidal NOM removal and membrane fouling reduction. The results showed that coagulation did not selectively remove colloidal NOM and the optimal coagulant dose was primarily determined by the concentration of humic substances. Comparatively, MIEX pretreatment preferentially removed humic substances and reduced the coagulant dose needed for colloidal NOM removal as a result of coagulation stoichiometry. A matched-pair analysis showed that integrated MIEX and coagulation pretreatment at much lower coagulant doses was as effective as coagulation in reducing membrane fouling. It is concluded that integrated MIEX and coagulation is potentially a viable pretreatment approach to reduce membrane fouling and in general removal of colloidal NOM in feedwater is an effective approach for membrane fouling control and should be considered in the research, development, and application of novel LPM-based treatment processes.

Durability of an aromatic block copolymer membrane in practical PEFC operation

The durability of a novel proton-conducting polymer electrolyte membrane, sulfonated polybenzophenone/poly (arylene ether) (SPK) block copolymer, was evaluated at middle temperature (80°C), low humidity (53% RH), and a low current density, 0.02Acm−2, in a polymer electrolyte fuel cell for 980h. The electrochemical properties and drain water collected from the anode and cathode were monitored during the test, followed by post-test analyses of the membrane. The nuclear magnetic resonance (NMR) spectra and ion exchange capacity (IEC) value of the post-test membrane showed very minor changes compared to those of the pristine one. The post-test membrane retained 94% of its original weight-averaged molecular weight (Mw)org. There was no remarkable change in Qoxide (oxide formation charge of the cathode catalyst) after the test, which indicates that the specific adsorption of decomposition products of the SPK membrane on the cathode catalyst was not significant.

Hybrid Treatment Process of using MIEX and High Performance Composite Coagulant for DOM and Bromide Removal

Dissolved organic matter (DOM) and bromide, two primary precursors of disinfection by-products, cannot be effectively removed by conventional coagulation processes. Alternative methods are required to ensure the safety of drinking water. The effectiveness of using magnetic ion exchange resin (MIEX) and high-performance coagulant (HPAC) in a hybrid process for the removal of turbidity, DOM, and bromide in raw water supplies was investigated. Results showed that a wide range of DOM, with different molecular weights (MWs) con- taining soluble microbial byproduct-like organic matters, aromatic protein, and fulvic/humic acid, was removed by MIEX in the two studied water sources. In addition, up to 91% of bromide was removed in bromide spiked raw waters. In comparison, HPAC coagulation did not effectively eliminate low MW or soluble microbial byproduct-like organic matters in raw water. The combined MIEX and HPAC process more significantly improved the performance of turbidity, DOM, and bromide removal than coagulation alone. With MIEX pretreatment, the requisite HPAC dosage was reduced by at least 67%. DOI: 10.1061/(ASCE)EE.1943-7870.0000622. © 2013 American Society of Civil Engineers. CE Database subject headings: Turbidity; Coagulation; Waste treatment; Abatement and removal; Disinfection; Organic matter. Author keywords: Dissolved organic matter; Bromide; Turbidity; Magnetic ion exchange resin; Enhanced coagulation; Coagulation; Drinking water; Ion exchange; Water quality.

Effects of magnetic ion exchange pretreatment on low pressure membrane filtration of natural surface water

Magnetic ion exchange (MIEX) pretreatment has been increasingly employed by water treatment plants for removal of dissolved organic carbon (DOC). In this study, the effects of MIEX pretreatment on low pressure membrane filtration of natural surface water were investigated under different feedwater qualities, membrane properties, and MIEX dosing conditions. Regardless of feedwater DOC, moderate decrease in the total and hydraulically irreversible fouling was observed for a polyvinylidene fluoride (PVDF) microfiltration membrane and a polyethersulfone ultrafiltration (UF) membrane after MIEX pretreatment, which was coincident with moderate removals of high molecular weight DOC in the feedwaters. Comparatively, the fouling of a PVDF UF membrane did not decrease after MIEX pretreatment, revealing the impact of membrane properties on membrane fouling in the presence of MIEX pretreatment. Reuse of virgin or regenerated MIEX resulted in similar membrane fouling as observed with single use of the virgin MIEX. The level of DOC removal by MIEX was similar to the removal of MS2 bacteriophage spiked in the feedwater, suggesting a potential similarity in the removal of organic and microbial particles. In conclusion, MIEX pretreatment was effective for DOC removal, but less effective in controlling short-term membrane fouling or removing viruses.

Using UV Spectroscopy and Molecular Weight Determinations to Investigate the Effect of Various Water Treatment Processes on NOM Removal: Australian Case Study

AbstractNatural organic material (NOM) has been the focus of many studies because of its ability to compromise water treatment processes. This case study utilized ultraviolet (UV) spectroscopy and molecular weight distributions to investigate the impact of six water treatment processes (alum coagulation, magnetic ion exchange (MIEX) resin treatment, chlorination, ozonation, powdered activated carbon (PAC) adsorption, and biological sand filtration) on the removal of NOM from an Australia water source, Myponga Reservoir. Each of these processes displayed different effects on the concentration and character of NOM. The removal of dissolved organic carbon (DOC) and UV absorbance at 254 nm (UV254) by MIEX and the biological sand filter was shown to follow first-order kinetics with rate constants ranging from 9.0×10−8 s−1 (biological sand filter) to 6.3×10−5 s−1 (MIEX treatment). UV spectroscopic investigations showed the potential to predict the formation of disinfection by-products from chlorination with s...

Evaluation of coagulation (FeCl3) and anion exchange (MIEX) for stabilized landfill leachate treatment and high-pressure membrane pretreatment

Laboratory-scale experiments were conducted to assess the effectiveness of coagulation (ferric chloride – FeCl3) and magnetic ion exchange (MIEX) as a pretreatment option for treating stabilized landfill leachate using reverse osmosis (RO) and nanofiltration (NF) membranes. Leachate from three different landfills was collected and characterized as stabilized leachate with a ratio of biochemical oxygen demand to chemical oxygen demand in the range of 0.02–0.11. Batch jar-tests were conducted to determine the effectiveness of FeCl3 and MIEX. A maximum reduction of 71% and 34% dissolved organic carbon (DOC) and 94% and 48% UV-254 absorbing organic matter (OM) was observed using FeCl3 and MIEX, respectively. Effective doses of FeCl3 (22mmolL−1) and MIEX (5mLL−1) were selected for leachate pretreatment before membrane operation. Batch RO and NF membrane experiments were conducted with raw and pretreated leachates to study the change in permeate flux for each type of membrane and leachate. Even though the pretreated leachate contained over 45% less UV-254 absorbing OM than raw leachate, leachate pretreatment did not increase the permeate flux as compared to raw leachate during RO and NF membrane treatment. The potential cause of the decrease in permeate flux in pretreated leachate as compared to raw leachate was hypothesized as the change in characteristics of pretreated leachate and membrane surfaces caused by the continuous increase in pH of pretreated leachate.

Comparison of drinking water treatment process streams for optimal bacteriological water quality

Four pilot-scale treatment process streams (Stream 1 – Conventional treatment (coagulation/flocculation/dual media filtration); Stream 2 – Magnetic ion exchange (MIEX)/Conventional treatment; Stream 3 – MIEX/Conventional treatment/granular activated carbon (GAC) filtration; Stream 4 – Microfiltration/nanofiltration) were commissioned to compare their effectiveness in producing high quality potable water prior to disinfection. Despite receiving highly variable source water quality throughout the investigation, each stream consistently reduced colour and turbidity to below Australian Drinking Water Guideline levels, with the exception of Stream 1 which was difficult to manage due to the reactive nature of coagulation control. Of particular interest was the bacteriological quality of the treated waters where flow cytometry was shown to be the superior monitoring tool in comparison to the traditional heterotrophic plate count method. Based on removal of total and active bacteria, the treatment process streams were ranked in the order: Stream 4 (average log removal of 2.7) > Stream 2 (average log removal of 2.3) > Stream 3 (average log removal of 1.5) > Stream 1 (average log removal of 1.0). The lower removals in Stream 3 were attributed to bacteria detaching from the GAC filter. Bacterial community analysis revealed that the treatments affected the bacteria present, with the communities in streams incorporating conventional treatment clustering with each other, while the community composition of Stream 4 was very different to those of Streams 1, 2 and 3. MIEX treatment was shown to enhance removal of bacteria due to more efficient flocculation which was validated through the novel application of the photometric dispersion analyser.

Corrigendum: Water Science and Technology: Water Supply 11(1), 7–14: Impact of magnetic ion exchange resin pretreatment on alleviating UF membrane fouling, H. Xu, W. Chen, J. Sun and Z. Yuan

Correction| March 01 2012 Corrigendum: Water Science and Technology: Water Supply 11(1), 7–14: Impact of magnetic ion exchange resin pretreatment on alleviating UF membrane fouling, H. Xu, W. Chen, J. Sun and Z. Yuan Water Supply (2012) 12 (2): 258. https://doi.org/10.2166/ws.2012.010 Views Icon Views Article contents Figures & tables Video Audio Supplementary Data Share Icon Share Twitter LinkedIn Tools Icon Tools Cite Icon Cite Permissions Search Site Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentAll JournalsThis Journal Search Advanced Search Citation Corrigendum: Water Science and Technology: Water Supply 11(1), 7–14: Impact of magnetic ion exchange resin pretreatment on alleviating UF membrane fouling, H. Xu, W. Chen, J. Sun and Z. Yuan. Water Supply 1 March 2012; 12 (2): 258. doi: https://doi.org/10.2166/ws.2012.010 Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex This content is only available as a PDF. © IWA Publishing 2012 Article PDF first page preview Close Modal You do not currently have access to this content.

Secondary effects of anion exchange on chloride, sulfate, and lead release: Systems approach to corrosion control

Water treatment processes can cause secondary changes in water chemistry that alter finished water quality including chloride, sulfate, natural organic matter (NOM), and metal release. Hence, the goal of this research was to provide an improved understanding of the chloride-to-sulfate mass ratio (CSMR) with regards to chloride and sulfate variations at full-scale water treatment plants and corrosion potential under simulated premise plumbing conditions. Laboratory corrosion studies were conducted using Pb–Sn solder/Cu tubing galvanic cells exposed to model waters with low (approx. 5 mg/L Cl− and 10 mg/L SO42–) and high (approx. 50 mg/L Cl− and 100 mg/L SO42–) concentrations of chloride and sulfate at a constant CSMR of ∼0.5. The role of NOM during corrosion was also evaluated by changing the type of organic material. In addition, full-scale sampling was conducted to quantify the raw water variability of chloride, sulfate, and NOM concentrations and the changes to these parameters from magnetic ion exchange treatment. Test conditions with higher concentrations of chloride and sulfate released significantly more lead than the lower chloride and sulfate test waters. In addition, the source of NOM was a key factor in the amount of lead released with the model organic compounds yielding significantly less lead release than aquatic NOM.

Anion exchange pretreatment for the removal of natural organic matter from humic rich water

The treatment of humic rich water using anion exchange, coagulation and PAC-adsorption was studied, both independently and in sequence in that order. The commercial aluminium-based coagulant PAX-16, powdered activated carbon W35 and the magnetic ion exchange resin (MIEX®) were used in the study. The source of humic substances was natural water (25.0 g C/m3 as DOC) flowing out from the Great Batorow Peat-Bog (Lower Silesia, Poland). In addition to DOC, color, UV254 absorbance, specific UV absorbance (SUVA254), turbidity, pH and alkalinity were also analyzed. Regardless of the applied technology, in the phase of raw water treatment extraordinary solutions were necessary to treat the humic rich water – a high coagulant (13.1 g Al/m3) or PAC (>200 mg/dm3) dose or a low bed volume (200 BVs) in the case of anion exchange. MIEX®DOC pretreatment had a very positive influence on the course and effects of coagulation resulting in a higher coagulant efficiency for removing organic compounds. In this respect, MIEX®DOC pretreatment allowed the application of a required coagulant dose four times lower compared to the coagulation of raw water. In testing the sequence of processes (MIEX®DOC – coagulation – PAC-adsorption), coagulation was the main process responsible for reducing the SUVA254 value. The improvement in water quality after PAC-adsorption was not significant, although the process removed DOC fractions that could not be removed by coagulation. Each of the applied methods played a role in the treatment of humic rich water and the nearly complete removal of NOM was achieved (in the sequence of processes) under relatively rational operating conditions for the treatment techniques.

Importance of the order in enhancing EfOM removal by combination of BAC and MIEX®

Biological activated carbon (BAC) is operationally a simple treatment which can be employed to remove effluent organic matter (EfOM) from secondary wastewater effluent (SWWE). Unfortunately, BAC removes only a limited amount of dissolved organic carbon (DOC). Thus, maximizing DOC removal from SWWE using BAC is a major concern in wastewater reuse. This study has investigated a hybrid system of BAC and Magnetic Ion Exchange Resin (MIEX(®)) for the enhanced removal of DOC. Performance of both BAC prior to MIEX(®) (BAC/MIEX(®)) and reverse (MIEX(®)/BAC) combination was evaluated in terms of DOC removal. The BAC/MIEX(®) showed much better DOC removal. This is because microbial activity in the BAC bed converted MIEX(®) non-amenable DOC to MIEX(®) amenable DOC. As a result, BAC/MIEX(®) combination synergised DOC removal. In addition, BAC was also found to be highly effective in reducing MIEX(®) dose for a given DOC removal from SWWE.

The Removal of Inorganic Anions from Municipal Secondary Effluent Using Magnetic Ion Exchange Resin

The primary objective of this research was to evaluate the effectiveness of a magnetic ion exchange process (MIEX) in removing inorganic anions from municipal secondary effluent. Municipal secondary effluent drew from Gaobeidian wastewater treatment plant treating about 800,000 m3/day domestic wastewater. In the pilot experiment, MIEX resin removed 37.01% phosphorus, 31.62% nitrate, 36.06% ammonium and 64.34% sulphate from municipal secondary effluent. Phosphorus concentration in resin influent influenced reclaimed water treatment efficiency. Phosphorus removal rate was positively correlated with the concentration in influent. If phosphorus concentration in influent was >0.82mg/L, phosphorus removal of >52% was achieved. Nitrate and sulphate removal had same variation laws. 18.92% average removal rate of nitrate in middle period was lower than 35.06% and 39.25% average removal rates in earlier and latter periods respectively. The average removal rates of ammonium in three periods were 83.03%, 43.51% and 84.29% respectively. Removed ammonium of each sample was about 0.250mg/L, average removal rate was 36.06%. Lower ammonium concentration in influent could cause higher removal rate. Otherwise, magnetic ion exchange process could increase turbidity and could not disinfect, the resin effluent will be treated with coagulation-sedimentation and ozonation for groundwater recharge research with reclaimed water.

Arsenic Removal from Water Using Various Adsorbents: Magnetic Ion Exchange Resins, Hydrous Ion Oxide Particles, Granular Ferric Hydroxide, Activated Alumina, Sulfur Modified Iron, and Iron Oxide-Coated Microsand

The equilibrium and kinetic adsorption of arsenic on six different adsorbents were investigated with one synthetic and four natural types (two surface and two ground) of water. The adsorbents tested included magnetic ion exchange resins (MIEX), hydrous ion oxide particles (HIOPs), granular ferric hydroxide (GFH), activated alumina (AA), sulfur modified iron (SMI), and iron oxide-coated mic rosand (IOC-M), which have different physicochemical properties (shape, charge, surface area, size, and metal content). The results showed that adsorption equilibriums were achieved within a contact period of 20 min. The optimal doses of adsorbents determined for a given equilibrium concentration of Ceq = 10 µg/L were 500 mg/L for AA and GFH, 520–1,300 mg/L for MIEX, 1,200 mg/L for HIOPs, 2,500 mg/L for SMI, and 7,500 mg/L for IOC-M at a contact time of 60 min. At these optimal doses, the rate constants of the adsorbents were 3.9, 2.6, 2.5, 1.9, 1.8, and 1.6 1/hr for HIOPs, AA, GFH, MIEX, SMI, and IOC-M, respectively. The presence of silicate significantly reduced the arsenic removal efficiency of HIOPs, AA, and GFH, presumably due to the decrease in chemical binding affinity of arsenic in the presence of silicate. Additional experiments with natural types of water showed that, with the exception of IOC-M, the adsorbents had lower adsorption capacities in ground water than with surface and deionized water, in which the adsorption capacities decreased by approximately 60–95%.