Removal of boron from seawater by selective ion exchange resins

Reverse osmosis (RO) desalination process is an efficient and reliable membrane technology for the production of drinking water from seawater. However, some serious limitations had recently been discovered during the field practice. Boron problem is one of them. According to the WHO regulations, the boron concentration should be lower than 0.5 mg/L in drinking water. It is still difficult to reduce boron level to 0.5 mg/L or lower with the conventional reverse osmosis desalination plants equipped with commercially available RO membranes. Therefore, more efficient separation technologies are needed for boron removal.In this study, the performance of the boron-selective ion exchange resins containing N-methyl glucamine groups, as Diaion CRB 02 and Dowex XUS 43594.00, have been tested for boron removal from model seawater. The kinetic performances of these resins were compared. The kinetic data obtained were evaluated using Lagergren pseudo-first-order and second-order models. Also, the process kinetics were predicted by using diffusion models. In addition, column-mode tests have been carried out for boron removal from model seawater.     

Boron removal from water and its recovery using iron (Fe) oxide/hydroxide-based nanoparticles (NanoFe) and NanoFe-impregnated granular activated carbon as adsorbent

This study presents information obtained by the synthesis of Fe(3) oxide/hydroxide nanoparticles sol (NanoFe) and NanoFe-impregnated granular activated carbon as adsorbents for boron removal from solutions. The research describes an adsorption method for cleaning a solution containing boron contaminants followed by recovery of the adsorbent and the adsorbed material for safe removal or further reuse. The technology provides an efficient method of boron removal from water. A marked effect of NanoFe and NanoFe-impregnated GAC adsorbents concentration and pH level on boron removal efficiency was demonstrated. At least 95–98% boron recovery efficiency is possible using NanoFe sol and Fe-impregnated GAC that in fact also recover the adsorbent for reuse. Boron adsorption onto the NanoFe-impregnated GAC adsorbent may be described by pseudo-second-order reaction kinetics and the Langmuir isotherm model. The boron adsorption capacity on iron (3) oxide nanoparticles and Fe-impregnated GAC at an equilibrium concentration of 0.3 mg/dm³ as B in the solution is much higher than these values for similar adsorbents reported in the literature.     

氨基丙二醇功能化硼螯合树脂的制备及其硼酸吸附性能

分别用3-氨基-1,2-丙二醇（3-APD）和2-氨基-1,3-丙二醇（2-APD）对多孔氯甲基聚苯乙烯树脂（CMPS）进行修饰,制备得到含邻、间位二羟基官能团的硼螯合树脂：PS-3-APD和PS-2-APD。用傅里叶红外光谱仪（FTIR）、元素分析仪（EA）、压汞仪（MIP）和激光粒度仪（LPS）对材料进行表征,确认功能单体成功接枝于氯球上。对两种树脂进行了静态提硼性能研究,分别考察了原料液pH、初始硼酸浓度、外来金属离子对硼酸吸附量的影响,当溶液pH为9.15～9.20时,两种树脂对硼酸吸附量最大;溶液中Na⁺、Mg²⁺、Ca²⁺的存在会一定程度削弱树脂对硼酸吸附性能。吸附动力学表明其吸附速率较快,且均满足准二级动力学模型。与Freundlich相比,吸附等温线更符合Langmuir模型,拟合得到的理论最大吸附量分别为0.730mmol/g和0.868mmol/g。本文对未来新型硼螯合树脂的开发及工业化应用提供参考和指导。     

Boron removal from saline water: A comprehensive review

Boron is an essential micronutrient for plants and animals as well as a useful component for numerous industries. It is necessary to produce low boron containing water from RO desalination plants for both human consumption and for agriculture. For plants, a small amount of boron is necessary for their growth and development, but boron becomes toxic if the amount is slightly greater than required. Desalinated seawater from RO plants often contains high boron content and, when used for irrigation, has been proven to be damaging to crops including blackberry, lemon, and grapefruit. Apart from the toxic effects of boron on plants, boron should be removed from RO desalination plants to comply with the current guideline value, 0.5 mg/L, for potable water issued by the World Health Organisation (WHO). Currently there is no simple method to remove boron from saline water. The use of multi-pass reverse osmosis membrane (RO) with pH modification and the use of ion exchange using boron selective resins (BSRs) have both been considered as effective methods for the removal of boron. A hybrid process, Adsorption Membrane Filtration (AMF), has received attention as an emerging technology for boron removal with a high efficiency and low operating costs. The purpose of this review is to give an overview on boron in general and to discuss its toxicity. The problems of boron in the MENA (Middle East and North Africa) region are discussed as well as technologies, current and future, for the removal of boron from seawater. The focus is placed on current RO and ion exchange methodologies using BSRs as well as the future for the AMF method. The fundamentals of each process, the effects of experimental parameters, and findings are discussed.     

盐湖卤水提硼萃取剂的研究进展

溶剂萃取法是一种有工业应用前景的盐湖卤水提硼方法,而萃取分离的核心问题在于萃取剂的选择。为此,本文综述了近几年国内外盐湖卤水提硼萃取剂类型及其萃取效果,按照萃取剂结构和萃取方法将提硼萃取剂划分为脂肪醇（包括一元脂肪醇和二元脂肪醇）、芳香醇、混合醇等三部分加以叙述,着重介绍了应用最广的两种萃取剂,即2-乙基己醇和2-乙基-1,3-己二醇的研究与应用情况。同时介绍了大量新型结构的?-二醇类萃取剂,指出了今后提硼萃取剂的设计合成的发展趋势,为盐湖卤水萃取提硼工艺开发中萃取剂的选择提供重要参考。     

水中硼的去除方法研究进展

硼广泛应用于现代工业的各个领域,随之而来的含硼废水也开始引起人们的关注。苦咸水和海水由于硼含量较高,作为饮用水或灌溉水之前必须进行除硼处理。水中硼的去除方法逐渐成为人们关注和研究的热点之一。概述了硼的相关环境标准及水中硼的去除方法,分析了各种方法的优缺点,探讨了除硼方法的发展趋势。     

Non-equilibrium sorption modeling for boron removal from geothermal water using sorption-microfiltration hybrid method

In this study, the boron removal performance of a hybrid system composed of ground ion exchange resin particles coupled with a microfiltration separation unit was investigated. A non-equilibrium sorption modeling approach was introduced so as to understand the contributions of mass transfer resistances on the effluent stream concentration profiles, as well as on the resin loading scheme of this sorption-microfiltration hybrid system. This modeling approach allowed us to suggest new system operations and/or scale-up processes of sorption-microfiltration hybrid systems. In this study, the highly porous crosslinked boron selective chelating resins Diaion CRB02 and Dowex XUS 43594.00 containing N-methyl-glucamine group were used. Geothermal water that has high levels of boron was fed into the stirred cell element of the microfiltration system. Kinetic behaviour of boron selective resins for boron removal from geothermal water by the microfiltration system was evaluated to investigate the effects of resin particle size, resin concentration, and permeate flow rate.     

Removal of fluoride using some lanthanum(III)‐loaded adsorbents with different functional groups and polymer matrices

Although fluoride is beneficial for human beings in small quantities, it causes dental fluorosis when consumed in larger quantities over a period of time. In recent years, considerable work has been conducted for the purpose of developing new and low cost absorbents for adsorptive removal of fluoride, especially chelating resins loaded with metal ions. In the present study, several types of adsorbents with different functional groups loaded with lanthanum(III) were prepared to be used for fluoride removal from water. The optimum conditions for loading lanthanum(III) on the adsorbents and the effects of pH and initial fluoride concentration as well as shaking time and solid–liquid ratio on the removal of fluoride have been investigated. Based on these fundamental data, the removal of fluoride from actual hot spring water was also tested as a practical application by comparing the efficiency of different adsorbents for the removal of fluoride from hot spring water. The following conclusions were obtained. (1) The different chemical composition and chemical structure of the polymer matrix play the most important role in fluoride adsorption, (2) strongly acidic adsorbents are more effective on fluoride removal at neutral pH than weakly acidic adsorbents, (3) the order of fluoride removal in the neutral pH range of 4.5–8.0 by the different La(III)‐loaded adsorbents employed in the present work is as follows: 200CT resin > POJRgel > IR124resin > SOJR gel ≥ CPAgel ≥ WK11 resin. The column experiments showed that the 200CT resin loaded with lanthanum(III) at pH 6.0 can be successfully employed for the removal of fluoride ions from actual hot spring water. Copyright © 2003 Society of Chemical Industry     

Effect of Ionic Strength of Solution on Boron Mass Transfer by Ion Exchange Separation

Abstract

In the present study, batch kinetic tests have been performed for boron removal from model solutions using boron selective ion exchange resins Diaion CRB 02, Dowex (XUS 43594.00) and Purolite S 108. Several kinetic models have been used to evaluate the sorption kinetics of boron by means of a well mixed stirred system, diffusional models, pseudo‐first‐order, and pseudo‐second‐order kinetic models. The mass transfer model, based on a well stirred system including maximum capacity (Q_m, mg/g) and Langmuir constant (b, L/mg) values obtained from Langmuir isotherms, has been used to obtain predictive concentration changes against time. The experimental results have been used to compare with the modelling data for different ionic strength media.     

Boron Removal by Anion Exchangers Impregnated with Citric and Tartaric Acids

Abstract

The separation of boron compounds, boric acid and borax, with anion-exchange resins, before and after impregnation with citric and tartaric acids, has been studied. Three different commercially available anion exchangers were selected for this study. The results indicate that ion-exchanging on the examined resins is not quite effective for the removal of boron from boric acid and borax water solution. The presence of citric or tartaric acid is essential for the enhancement of the sorption capacity above that observed for the untreated resins. Sorption data show that citric acid is a more effective impregnant than tartaric acid.     

Kinetic studies of adsorption of bitter principles and titratable acid from grapefruit juice

Measurement of the initial rates of removal of limonin and naringin from grapefruit juices by several polystyrene and polyacrylic adsorbents has allowed these adsorbents, in the forms as supplied, to be ranked in their order of kinetic effectiveness for removal of the two bitter principles. Partition coefficients of bitter principles between juice and polystyrene adsorbent resins show that the capacity of such resins for naringin increases with specific surface area, but the capacity for limonin appears to increase with specific pore volume. With respect to titratable acid, the two weak base resins, Amberlite IRA-93 and Duolite A378, were equally effective both kinetically and in their capacity for titratable acid; both adsorbed somewhat less than 1 mol of titratable acid from grapefruit juice per equivaient of weak base resin.     

Batch and column adsorption of perfluorooctane sulfonate on anion exchange resins and granular activated carbon

Perfluorooctane sulfonate (PFOS) has been detected widely in the natural water matrix and is persistent, bioaccumulative, and toxic. To prevent the adverse effects of PFOS contamination on human health and the environment, effective removal techniques are needed. Adsorption is considered an effective technique for PFOS removal. In this study, five anion exchange resins and granular activated carbon (GAC) were examined to evaluate their performance for the removal of PFOS in both batch and column experiments. Experimental adsorption data for all of the adsorbents exhibited a high correlation with the Freundlich isotherm (R² = 0.95 – 0.98). Most of the anion exchange resins demonstrated a higher adsorption capacity than the GAC. PFA300 had the highest adsorption capacity (455 mg/g). Continuous adsorption of PFOS was performed in column experiments using the same adsorbents that had been used in the batch experiments. The experimental breakthrough curves were set at C/C₀ = 0.1. PFA300 showed the longest operation time before reaching the breakthrough point. The Yoon and Nelson model was used to predict the half‐saturation time of the anion exchange resins. Moreover, the anion exchange resins exhibited high recovery of PFOS by an organic solvent. Continuous PFOS adsorption on a column can be achieved using anion exchange resins for water/wastewater treatment. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39782.     

Polymeric adsorbents for treatment of waste effluents

A significant advance in ion exchange resin and adsorbent technology has been the development of the macroreticular pore structure. Synthetic rotes have been developed for preparing both ion exchange resins and polymeric adsorbents of high surface area and pore volume. Syntheses have been developed to the degree that the surface area and pore.parameters can be widely varied. Several of these macroreticular polymers based upon the crosslinked styrene and acrylate systems are now available commercially. These polymeric adsorbents are hard, durable, insoluble spheres of high surface area and porosity. They are available in a variety of polarities. The nonpolar adsorbents are particularly effective for adsorbing nonpolar solutes from polar solvents. Conversely, the polar adsorbents are very effective for adsorbing polar solutes from nonpolar solvents. Of particular interest is the use of these polymeric adsorbents for the treatment of effluent wastes. In some cases it has been demonstrated that one can recover significant quantities of re-usable chemicals that more than pay for the waste, treatment. The use of the polymeric adsorbents for the treatment of phenolicwastes is an example. Other related applications include the removal of chlorinated pesticides, TNT residues, and other noxious compounds from waste effluents and water supplies.     

Impregnated activated carbon for environmental protection

Impregnated activated carbons are carbonaceous adsorbents which have chemicals finely distributed on their internal surface. The impregnation optimizes the existing properties of the activated carbon giving a synergism between the chemicals and the carbon. This facilitates the cost-effective removal of certain impurities from gas streams which would be impossible otherwise. For environmental protection, various qualities of impregnated activated carbon are available and have been used for many years in the fields of gas purification, civil and military gas protection and catalysis.     

NEW CATION EXCHANGE RESINS BASED ON POLYVINYL ALCOHOL CONTAINING CARBOXYL GROUPS FOR THE REMOVAL OF SOME TEXTILE CONTAMINANTS FROM AQUEOUS SOLUTIONS

Two cation exchange resins having carboxyl contents, 628 and 424 meq/100 g sample were prepared by free radical polymerization of acrylic acid in presence of polyvinyl alcohol aqueous solution using methylenebisacrylamide as a crosslinker and ammonium persulfate as an initiator. The prepared resins were characterized by investigation of their potentiometric titration, durability, water solubility, and swellability. The removal of Cu²⁺ ions (in the form of copper sulfate) from aqueous solution using these resins was studied under different conditions, including resin particle size, copper sulfate concentration, time, pH, liquor to resin ratio (LR), agitation speed, and resin capacity. A comparison was also held among the removal of other cations, namely Ni²⁺ and Co²⁺, in their sulfate forms. The resins were also utilized in the removal of some basic dyes from their aqueous solutions.     

Equilibrium and Kinetic Studies of Ni (II) Adsorption using Pineapple and Bamboo Stem Based Adsorbents

This work addresses the preparation and characterization of inexpensive adsorbents for the removal of Ni (II) from aqueous solutions. Activated carbon based adsorbents have been prepared from plant based biomass resources, namely Pineapple stem ( Ananas Comosus ) and Bamboo Stem ( Bambuseae ). Adopting phosphoric acid and heat treatment techniques, it has been observed that the bamboo stem activated charcoal (BSAC) and pineapple stem (PS) adsorbents had a BET surface area of 116 and 11.47 m ² /g, respectively. FTIR analysis indicated that various surface functional groups (such as C ≡ N stretching, stretching vibration of C = O, –CH₃ wagging and C–O stretching vibration) contribute towards Ni (II) adsorption. Batch mode adsorption experiments were conducted for these adsorbents in the range of 50–300 mg/L Ni (II) solution concentration, 2–10 pH, 15–300 min. contact time, and 0.02–0.1 g/50 mL dosage. The BSAC adsorbent has been characterized with a metal uptake and %removal of 121.72 mg/g and 92.47, respectively, which corresponds to 45% higher metal uptake than corresponding bamboo based adsorbents presented in the literature. Further experimentation with BSAC enabled to achieve activated charcoal with surface area values similar to that of the commercial activated carbon adsorbent. The bamboo adsorbent has also been evaluated to perform similar to the commercial activated carbon for the removal and recovery of Pd (II) from synthetic electroless plating solutions. Also, a conceptual cost analysis indicated and affirmed towards the potential of the BSAC adsorbents for waste water treatment applications.     

改性吸附剂去除废水中磷的应用研究进展

去除废水中过量的磷可以减缓水体富营养化。吸附除磷因具有能耗低、容量大、污染少等优点而备受关注，改性吸附剂则可在此基础上提高除磷的靶向性，拓宽操作条件，增大吸附容量。本文分析了改性硅酸盐类、改性金属氧化物类、改性固体废弃物类和聚合物类4类除磷吸附剂的改性方法和吸附性能。硅酸盐类吸附材料以及固体废弃物类材料除磷效果略差，但因来源丰富、价格低廉而具有极大的吸引力。聚合物类吸附剂具有高吸附容量、高选择性，但价格昂贵。金属（氢）氧化物具有出色的磷酸盐吸附性能，且选择性好、吸附速度快，这些化合物已被掺入到沸石、介孔二氧化硅和生物炭等材料中，进一步增强其吸附性能，并在工程材料应用中取得重大突破，主要包括磁性吸附剂和颗粒吸附剂。4类吸附剂的作用机理可归纳为两种：一种是吸附剂上的金属与磷酸盐离子发生配位反应，形成沉淀；另一种是酸性条件下吸附剂上的羟基质子化，使羟基带正电，质子化的羟基通过静电吸引使磷得以去除。通过对不同类别吸附剂的吸附特性进行对比分析，提出将高分子技术运用到吸附剂制备过程中，开发同时具有较强解吸能力的改性吸附剂将成为除磷吸附剂研究的新热点。     

Newer applications for Crossflow Membrane Filtration

Traditionally, Crossflow Membrane Filtration has been used to concentrate and purify solutions of macromolecules. Typical applications include protein concentration in the Food, Dairy and Pharmaceutical industries. In recent years, the use of membranes to remove suspended solids and other unwanted components from liquid streams has been commercially proven. Such applications include clarification of fruit juices and other beverages as well as depyrogenation of water for both the Pharmaceutical and Electronics industry. Continuing development of larger pore microfiltration membranes are expanding the range of application to the removal of unwanted solids from solutions of proteins such as gelatin. This paper highlights recent data on the use of Croosflow Membrane Filtration in processing beverages, gelatin and inorganic slurries.     

REMOVAL OF BORON FROM BALÇOVA-IZMIR GEOTHERMAL WATER BY ION EXCHANGE PROCESS: BATCH AND COLUMN STUDIES

In this study, the efficiency of boron removal from Balçova geothermal water provided by the Izmir Geothermal Energy Company, Turkey, has been investigated using boron selective ion exchange resins Diaion CRB 02 and Dowex (XUS 43594.00) by batch and column methods. The results of the column studies have been evaluated in terms of type of resin and feed flow rate, and the effects of particle size and temperature have been investigated using the results obtained from batch kinetic studies. The data from the kinetic studies have been evaluated using pseudo-first-order and pseudo-second-order kinetics models. In addition, the classical diffusion models have been used to evaluate the kinetic data obtained to understand the rate-controlling mechanisms.     

基于纳米材料的静态吸附脱硫进展

综述了近年来新型纳米吸附剂静态吸附脱除燃料油中二苯并噻吩（DBT）的作用机理及最新研究进展。重点分析了金属骨架材料（MOFs）、分子印迹聚合物（MIPs）、石墨烯基材料、活性炭基材料（AC）、介孔微孔材料等不同吸附剂的研究现状,从脱硫机理角度探讨不同改性方法对吸附脱硫效果的影响。通过比较这些吸附脱硫材料的优缺点,展望未来吸附脱硫材料的发展趋势和前景,为开发更优良的吸附剂用于吸附脱除DBT提供一些研究思路。文章指出吸附脱除燃料油中的DBT目前的主要问题是吸附剂的重复利用、与燃料油接触容易产生污染和吸附剂与燃料油分离过程中造成的损耗,这些短板也是吸附脱硫法大规模工业应用的主要障碍,因此吸附材料的选择、改性方法以及机理研究是吸附脱除DBT的主要研究方向。