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Mutke XAM, Drees F, Lutze HV, Schmidt TC. Oxidation of the N-containing phosphonate antiscalants NTMP and DTPMP in reverse osmosis concentrates: Reaction kinetics and degradation rate. Chemosphere 2023; 341:139999. [PMID: 37643647 DOI: 10.1016/j.chemosphere.2023.139999] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Revised: 08/25/2023] [Accepted: 08/26/2023] [Indexed: 08/31/2023]
Abstract
N-containing organophosphonate antiscalants such as Aminotris (methylene phosphonic acid) (NTMP/ATMP) and Diethylenetriamine penta(methylene phosphonic acid) (DTPMP) are commonly used in reverse osmosis (RO) to prevent scaling, as well as to increase permeate yields. However, the concentrate in RO still contains antiscalants which can cause adverse effects in the environment such as mobilization of heavy metals. The abatement of antiscalants from RO concentrate can promote the precipitation of oversaturated scale-forming substances and reduce the risk of adverse environmental effects. In the present study, the degradation of NTMP and DTPMP as representatives for N-containing organophosphonate by ozone, hydroxyl radicals (•OH), and sulfate radicals (SO4•-) are studied regarding reaction kinetics and degradation in different matrices. The results show that NTMP and DTPMP react fast with ozone and sulfate radicals (formed in UV/persulfate). Reaction rate constants of ozone showed a strong pH dependency due to the dissociation of the amine. The apparent reaction rates for pH 7 have been determined to be kapp(NTMP + ozone) = 1.44 × 105 M-1 s-1 and kapp(DTPMP + ozone) = 1.16 × 106 M-1 s-1. Reaction kinetics of •OH and SO4•- did not play a distinctive pH dependency (k(•OH) = 109-1010 M-1 s-1 and k(SO4•-) = 107-108 M-1 s-1). Furthermore, real water experiments have shown that ozonation and UV/persulfate are effective tools to abate organophosphonates in RO concentrates. The formation of carcinogenic bromate in ozonation is minimized by the presence of N-containing organophosphonates presumably due to enhanced ozone consumption and scavenging of free bromine.
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Affiliation(s)
- Xenia A M Mutke
- Faculty of Chemistry, Instrumental Analytical Chemistry, University of Duisburg-Essen, Universitätsstraße 5, 45141, Essen, Germany
| | - Felix Drees
- Faculty of Chemistry, Instrumental Analytical Chemistry, University of Duisburg-Essen, Universitätsstraße 5, 45141, Essen, Germany
| | - Holger V Lutze
- IWW Water Centre, Moritzstraße 26, 45476, Mülheim an der Ruhr, Germany; Centre for Water and Environmental Research (ZWU), Universitätsstraße 5, 45141, Essen, Germany; Department of Civil and Environmental Engineering, Institute IWAR, Chair of Environmental Analytics and Pollutants, Technical University of Darmstadt, Franziska-Braun-Straße 7, 64287, Darmstadt, Germany.
| | - Torsten C Schmidt
- Faculty of Chemistry, Instrumental Analytical Chemistry, University of Duisburg-Essen, Universitätsstraße 5, 45141, Essen, Germany; IWW Water Centre, Moritzstraße 26, 45476, Mülheim an der Ruhr, Germany; Centre for Water and Environmental Research (ZWU), Universitätsstraße 5, 45141, Essen, Germany
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Mutke XAM, Tavichaiyuth K, Drees F, Lutze HV, Schmidt TC. Oxidation of the nitrogen-free phosphonate antiscalants HEDP and PBTC in reverse osmosis concentrates: Reaction kinetics and degradation rate. Water Res 2023; 233:119571. [PMID: 36841164 DOI: 10.1016/j.watres.2023.119571] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 11/20/2022] [Accepted: 01/03/2023] [Indexed: 06/18/2023]
Abstract
Reverse osmosis (RO) is an advanced technology used to produce potable water from a variety of water sources, including surface water, seawater and wastewater. The yield of the product water from the RO systems is increased by the addition of antiscalants which prevent scaling from calcium and other ions. Removal of antiscalants from RO concentrate can induce the precipitation of oversaturated scale-forming substances, enable additional water recovery from RO concentrates, and reduce the risk of eutrophication after concentrate disposal into the receiving water (e.g., river water). This study aims to provide a better insight into oxidation reactions of the N-free phosphonate antiscalants 1-hydroxyethane-1,1-diphosphonic acid (HEDP) and 2-phosphonobutane-1,2,4-tricarboxylic acid (PBTC) with ozone, hydroxyl radical (•OH) and sulfate radicals (SO4•-). Ozone barely reacts with HEDP and PBTC at pH 7 (k < 10 M-1s - 1), while second order reaction rates of SO4•- and •OH were determined to be in the range 107-108M - 1s - 1. Sulfate, silicate and chloride matrices increased HEDP ozone degradation rate possibly due to metal complexation effect. Whereas carbonate and chloride hindered PBTC ozone degradation, and natural organic matter (NOM) inhibited both HEDP and PBTC degradation through scavenging of •OH. The SO4•-- radical based oxidation process of HEDP and PBTC is mainly inhibited by carbonate and NOM, interestingly only HEDP degradation is inhibited by chloride whereby the PBTC could not be fully degraded (degradation < 60%). The oxidation of PBTC is in real RO concentrates in both processes limited to 10% degradation, whereas HEDP could be degraded up to 60% with ozone and UV/persulfate application.
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Affiliation(s)
- Xenia A M Mutke
- Instrumental Analytical Chemistry, University of Duisburg-Essen, Universitätsstr. 5, 45141 Essen, Germany
| | - Kittitouch Tavichaiyuth
- Instrumental Analytical Chemistry, University of Duisburg-Essen, Universitätsstr. 5, 45141 Essen, Germany
| | - Felix Drees
- Instrumental Analytical Chemistry, University of Duisburg-Essen, Universitätsstr. 5, 45141 Essen, Germany
| | - Holger V Lutze
- Civil- and Environmental Engineering, Institute IWAR, Technical University of Darmstadt, Franziska-Braun-Str. 7, 64287 Darmstadt, Germany; Centre for Water and Environmental Research (ZWU), University Duisburg-Essen, Universitätsstr. 2, 45141, Essen, Germany; IWW Water Centre, Moritzstr. 26, 45476 Mülheim an der Ruhr, Germany.
| | - Torsten C Schmidt
- Instrumental Analytical Chemistry, University of Duisburg-Essen, Universitätsstr. 5, 45141 Essen, Germany; Centre for Water and Environmental Research (ZWU), University Duisburg-Essen, Universitätsstr. 2, 45141, Essen, Germany; IWW Water Centre, Moritzstr. 26, 45476 Mülheim an der Ruhr, Germany
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Dai Z, Zhao Y, Paudyal S, Wang X, Dai C, Ko S, Li W, Kan AT, Tomson MB. Gypsum scale formation and inhibition kinetics with implications in membrane system. Water Res 2022; 225:119166. [PMID: 36198211 DOI: 10.1016/j.watres.2022.119166] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Revised: 09/18/2022] [Accepted: 09/23/2022] [Indexed: 06/16/2023]
Abstract
Water desalination using membrane technology is one of the main technologies to resolve water pollution and scarcity issues. In the membrane treatment process, mineral scale deposition and fouling is a severe challenge that can lead to filtration efficiency decrease, permeate quality compromise, and even membrane damage. Multiple methods have been developed to resolve this problem, such as scale inhibitor addition, product recovery ratio adjustment, periodic membrane surface flushing. The performance of these methods largely depends on the ability to accurately predict the kinetics of mineral scale deposition and fouling with or without inhibitors. Gypsum is one of the most common and troublesome inorganic mineral scales in membrane systems, however, no mechanistic model is available to accurately predict the induction time of gypsum crystallization and inhibition. In this study, a new gypsum crystallization and inhibition model based on the classical nucleation theory and a Langmuir type adsorption isotherm has been developed. Through this model, it is believed that gypsum nucleation may gradually transit from homogeneous to heterogeneous nucleation when the gypsum saturation index (SI) decreases. Such transition is represented by a gradual decrease of surface tension at smaller SI values. This model assumes that the adsorption of inhibitors onto the gypsum nucleus can increase the nucleus superficial surface tension and prolong the induction time. Using the new model, this study accurately predicted the gypsum crystallization induction times with or without nine commonly used scale inhibitors over wide ranges of temperature (25-90 °C), SI (0.04-0.96), and background NaCl concentration (0-6 mol/L). The fitted affinity constants between scale inhibitors and gypsum show a good correlation with those between the same inhibitors and barite, indicating a similar inhibition mechanism via adsorption. Furthermore, by incorporating this model with the two-phase mineral deposition model our group developed previously, this study accurately predicts the gypsum deposition time on the membrane material surfaces reported in the literature. We believe that the model developed in this study can not only accurately predict the gypsum crystallization induction time with or without scale inhibitors, elucidate the gypsum crystallization and inhibition mechanisms, but also optimize the mineral scale control in the membrane filtration system.
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Affiliation(s)
- Zhaoyi Dai
- State Key Laboratory of Biogeology and Environmental Geology, School of Earth Sciences, China University of Geosciences, Wuhan 430074, China; Hubei Key Laboratory of Critical Zone Evolution, School of Earth Sciences, China University of Geosciences, Wuhan 430074, China; Department of Civil and Environmental Engineering, Rice University, 6100 Main Street, Houston, TX 77005, United States.
| | - Yue Zhao
- Department of Civil and Environmental Engineering, Rice University, 6100 Main Street, Houston, TX 77005, United States; Research Institute of Petroleum Processing, SINOPEC, Beijing, China
| | - Samridhdi Paudyal
- Department of Civil and Environmental Engineering, Rice University, 6100 Main Street, Houston, TX 77005, United States
| | - Xin Wang
- Department of Civil and Environmental Engineering, Rice University, 6100 Main Street, Houston, TX 77005, United States
| | - Chong Dai
- Department of Civil and Environmental Engineering, Rice University, 6100 Main Street, Houston, TX 77005, United States
| | - Saebom Ko
- Department of Civil and Environmental Engineering, Rice University, 6100 Main Street, Houston, TX 77005, United States
| | - Wei Li
- Department of Civil and Environmental Engineering, Rice University, 6100 Main Street, Houston, TX 77005, United States
| | - Amy T Kan
- Department of Civil and Environmental Engineering, Rice University, 6100 Main Street, Houston, TX 77005, United States
| | - Mason B Tomson
- Department of Civil and Environmental Engineering, Rice University, 6100 Main Street, Houston, TX 77005, United States
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Li A, Zhang H, Liu Q, Zeng H. Effects of chemical inhibitors on the scaling behaviors of calcite and the associated surface interaction mechanisms. J Colloid Interface Sci 2022; 618:507-17. [PMID: 35366478 DOI: 10.1016/j.jcis.2022.03.105] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2022] [Revised: 03/24/2022] [Accepted: 03/24/2022] [Indexed: 11/20/2022]
Abstract
HYPOTHESIS It is hypothesized that the performance of a chemical inhibitor to interfere with the precipitation and scaling of calcite (calcium carbonate, CaCO3) is achieved through its chelating interaction with calcium ions. The effectiveness of a chemical inhibitor in removing existing scales from the mineral surfaces is proposed to rely on its ability to modify the calcite crystal structures. EXPERIMENTS Bulk scaling tests and dynamic adsorption experiments using a quartz crystal microbalance with dissipation monitoring were conducted to systematically investigate the scaling behaviours (i.e., buildup and breakup processes) of calcite crystals, in the absence and presence of chemical inhibitors, that include polyacrylic acid, sodium hexametaphosphate, 2-phosphonobutane-1,2,4-tricarboxylic acid, and diethylenetriamine penta(methylene phosphonic acid). Scanning electron microscope imaging and thermodynamic characterization using isothermal titration calorimetry were further applied to reveal the surface interactions that contributed to the differences among the effects of the four additives. FINDINGS The results indicate that sodium hexametaphosphate is most efficient in alleviating the amount of CaCO3 deposited by reducing the concentration of free Ca2+, and diethylenetriamine penta(methylene phosphonic acid) shows an outstanding ability to clean the mineral surface by destroying the ordered crystal layers of the scales so that they can be washed away with water. This work provides useful insights into the fundamental interactions of chemical inhibitors and calcite, with implications for the development of effective chemical solutions for anti-scaling and descaling applications.
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Huang N, Xu ZB, Wang WL, Wang Q, Wu QY, Hu HY. Elimination of amino trimethylene phosphonic acid (ATMP) antiscalant in reverse osmosis concentrate using ozone: Anti-precipitation property changes and phosphorus removal. Chemosphere 2022; 291:133027. [PMID: 34822865 DOI: 10.1016/j.chemosphere.2021.133027] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2021] [Revised: 11/08/2021] [Accepted: 11/20/2021] [Indexed: 06/13/2023]
Abstract
Amino trimethylene phosphonic acid (ATMP) was widely used as an antiscalant in reverse osmosis (RO) systems to prevent membrane scaling, and entered RO concentrate at elevated levels. However, phosphonate antiscalants in RO concentrate might aggravate phosphorus pollution, remobilize heavy metals, and adversely affect the sedimentation treatment of RO concentrate. Ozonation was found an efficient method for ATMP treatment. The ATMP removal efficiencies with 8 mg/L ozone were 100% and 86.5% for ultrapure water and RO concentrate, respectively. The ATMP mineralization efficiency reached 46.5% with 8 mg/L ozone. The rate constant for the reaction between ATMP and ozone was 1.92 × 106 M-1 s-1. Increasing the pH from 3 to 9 decreased the ATMP removal efficiency from 90% to 30.9% but increased the orthophosphate formation to ATMP removal ratio from 0.11 to 0.48. The ATMP intermediates generated with low ozone dosages exhibited moderate chelation and anti-precipitation capacity, and their chelation and anti-precipitation capacity could be further attenuated by increasing the ozone dosage. Ozonation alone enhanced the growth potential for microalgae in RO concentrate because orthophosphate formed. Combining ozonation and coagulation effectively removed 83.0% of the total phosphorus from RO concentrate. The maximum algal density of Scenedesmus sp. LX1 decreased by 78.7% by ozonation and coagulation.
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Affiliation(s)
- Nan Huang
- Environmental Simulation and Pollution Control State Key Joint Laboratory, State Environmental Protection Key Laboratory of Microorganism Application and Risk Control (SMARC), School of Environment, Tsinghua University, Beijing, 100084, PR China; Beijing Laboratory for Environmental Frontier Technologies, Beijing, 100084, China
| | - Zi-Bin Xu
- Environmental Simulation and Pollution Control State Key Joint Laboratory, State Environmental Protection Key Laboratory of Microorganism Application and Risk Control (SMARC), School of Environment, Tsinghua University, Beijing, 100084, PR China; Beijing Laboratory for Environmental Frontier Technologies, Beijing, 100084, China
| | - Wen-Long Wang
- Key Laboratory of Microorganism Application and Risk Control of Shenzhen, Guangdong Provincial Engineering Research Center for Urban Water Recycling and Environmental Safety, Institute of Environment and Ecology, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen, 518055, PR China.
| | - Qi Wang
- Environmental Simulation and Pollution Control State Key Joint Laboratory, State Environmental Protection Key Laboratory of Microorganism Application and Risk Control (SMARC), School of Environment, Tsinghua University, Beijing, 100084, PR China; Beijing Laboratory for Environmental Frontier Technologies, Beijing, 100084, China
| | - Qian-Yuan Wu
- Key Laboratory of Microorganism Application and Risk Control of Shenzhen, Guangdong Provincial Engineering Research Center for Urban Water Recycling and Environmental Safety, Institute of Environment and Ecology, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen, 518055, PR China
| | - Hong-Ying Hu
- Environmental Simulation and Pollution Control State Key Joint Laboratory, State Environmental Protection Key Laboratory of Microorganism Application and Risk Control (SMARC), School of Environment, Tsinghua University, Beijing, 100084, PR China; Research Institute for Environmental Innovation (Suzhou), Tsinghua, Jiangsu, Suzhou, 215163, China
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Wang Z, Chen G, Patton S, Ren C, Liu J, Liu H. Degradation of nitrilotris-methylenephosphonic acid (NTMP) antiscalant via persulfate photolysis: Implications on desalination concentrate treatment. Water Res 2019; 159:30-37. [PMID: 31078749 DOI: 10.1016/j.watres.2019.04.051] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Revised: 04/22/2019] [Accepted: 04/27/2019] [Indexed: 06/09/2023]
Abstract
Nitrilotris-methylenephosphonic acid (NTMP) has been widely used as an antiscalant in reverse osmosis (RO) desalination and other industrial processes to inhibit scaling from calcium and other hardness ions. Removal of NTMP from RO concentrate can induce the precipitation of oversaturated scale-forming substances, enable additional water recovery from RO concentrate, and reduce the risk of eutrophication after brine disposal. This study investigated the kinetics and mechanisms of oxidative degradation of NTMP by UV photolysis of persulfate at 254 nm. Results showed that NTMP was effectively degraded by persulfate photolysis and the reaction followed pseudo first-order kinetics. The degradation of NTMP was favorable at circumneutral pHs but significantly inhibited in highly alkaline conditions (e.g., pH of 11.5), mainly due to the reduced concentration of SO4•-. Using a competition reaction kinetics approach, the second-order rate constants of NTMP with SO4•- and HO• were determined to be (2.9 ± 0.6) × 107 M-1s-1 and (1.1 ± 0.1) × 108 M-1s-1, respectively. SO4•- had a predominant contribution to NTMP degradation (62%-95%), because the steady-state concentration of SO4•- was 11-54 times higher than that of HO• at pHs between 4 and 11.5. NTMP degradation rate increased with an increase in persulfate dosage and a decrease in NTMP concentration. In the real RO concentrate, NTMP degradation rate was impacted by the presence of chloride and bicarbonate. The degradation of NTMP started with the cleavage of C-N bonds, and then generated intermediates including iminodi(methylene)phosphonate, hydroxymethylphosphonic acid and aminotris(methylenephosphonic acid), which were eventually mineralized into ammonia, phosphate and carbon dioxide. This study demonstrated that UV/persulfate is a promising technology to remove phosphonate antiscalants from RO concentrate.
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Affiliation(s)
- Zhi Wang
- Key Laboratory for Environment and Disaster Monitoring and Evaluation, Hubei, Institute of Geodesy and Geophysics, Chinese Academy of Sciences, Wuhan, 430077, China; Department of Chemical and Environmental Engineering, University of California, Riverside, CA, 92521, USA
| | - Gongde Chen
- Department of Chemical and Environmental Engineering, University of California, Riverside, CA, 92521, USA
| | - Samuel Patton
- Department of Chemical and Environmental Engineering, University of California, Riverside, CA, 92521, USA
| | - Changxu Ren
- Department of Chemical and Environmental Engineering, University of California, Riverside, CA, 92521, USA
| | - Jinyong Liu
- Department of Chemical and Environmental Engineering, University of California, Riverside, CA, 92521, USA
| | - Haizhou Liu
- Department of Chemical and Environmental Engineering, University of California, Riverside, CA, 92521, USA.
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Huang N, Wang WL, Xu ZB, Wu QY, Hu HY. UV/chlorine oxidation of the phosphonate antiscalant 1-Hydroxyethane-1, 1-diphosphonic acid (HEDP) used for reverse osmosis processes: Organic phosphorus removal and scale inhibition properties changes. J Environ Manage 2019; 237:180-186. [PMID: 30784866 DOI: 10.1016/j.jenvman.2019.02.055] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2018] [Revised: 02/01/2019] [Accepted: 02/09/2019] [Indexed: 06/09/2023]
Abstract
Reverse osmosis (RO) technology plays an increasingly important role in municipal wastewater reclamation. However, the antiscalants used in RO systems showed adverse effects to the ecosystem: impending the removal of hardness from RO concentrates; inducing phosphorus pollution in receiving water; enhancing the trace metal migration in the environment. In this study, UV/chlorine advanced oxidation process was used to oxidize a typical phosphoric antiscalant (1-Hydroxyethane-1, 1-diphosphonic Acid, HEDP). UV/chlorine showed significant synergetic effects on HEDP degradation compared to UV irradiation or chlorination alone. Compared to UV/H2O2 oxidation, UV/chlorine process is more efficient for HEDP transformation with chlorine dosages ranging from 0.1 to 0.4 mmoL/L. Chorine dosage showed dual effects on HEDP oxidation by UV/chlorine: the increasing trend of transformation efficiency of HEDP got slower with increasing chlorine dosage. The transformation efficiency of HEDP by UV/chlorine oxidation decreased from 39% to 14% with pH increasing from 4.5 to 9.0, likely due to the higher quantum yields and lower radical quenching rates of HOCl than those of OCl-. The transformation efficiency of HEDP decreased 14% and 42% with 30 mM of chloride and bicarbonate, respectively. The presence of nitrate promoted the oxidation of HEDP by UV/chlorine: the transformation efficiency increased 5% and 83% with the presence of 5 mM and 30 mM nitrate, respectively. Based on the static scale inhibition tests, UV/chlorine oxidation is effective at removing the scale inhibition ability of HEDP. During UV/chlorine process, the maximum scale inhibition ratio decreased from 66% to 34% as the removal of phosphonate ligand from HEDP increased to 80%.
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Affiliation(s)
- Nan Huang
- Environmental Simulation and Pollution Control State Key Joint Laboratory, State Environmental Protection Key Laboratory of Microorganism Application and Risk Control (SMARC), School of Environment, Tsinghua University, Beijing 100084, PR China
| | - Wen-Long Wang
- Environmental Simulation and Pollution Control State Key Joint Laboratory, State Environmental Protection Key Laboratory of Microorganism Application and Risk Control (SMARC), School of Environment, Tsinghua University, Beijing 100084, PR China; Shenzhen Laboratory of Microorganism Application and Risk Control, Guangdong Provincial Engineering Research Center for Urban Water Recycling and Environmental Safety, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055, People's Republic of China
| | - Zi-Bin Xu
- Environmental Simulation and Pollution Control State Key Joint Laboratory, State Environmental Protection Key Laboratory of Microorganism Application and Risk Control (SMARC), School of Environment, Tsinghua University, Beijing 100084, PR China
| | - Qian-Yuan Wu
- Shenzhen Laboratory of Microorganism Application and Risk Control, Guangdong Provincial Engineering Research Center for Urban Water Recycling and Environmental Safety, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055, People's Republic of China.
| | - Hong-Ying Hu
- Environmental Simulation and Pollution Control State Key Joint Laboratory, State Environmental Protection Key Laboratory of Microorganism Application and Risk Control (SMARC), School of Environment, Tsinghua University, Beijing 100084, PR China; Shenzhen Environmental Science and New Energy Technology Engineering Laboratory, Tsinghua-Berkeley Shenzhen Institute, Shenzhen 518055, PR China.
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Xu ZB, Wang WL, Huang N, Wu QY, Lee MY, Hu HY. 2-Phosphonobutane-1,2,4-tricarboxylic acid (PBTCA) degradation by ozonation: Kinetics, phosphorus transformation, anti-precipitation property changes and phosphorus removal. Water Res 2019; 148:334-343. [PMID: 30391862 DOI: 10.1016/j.watres.2018.10.038] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Revised: 09/30/2018] [Accepted: 10/13/2018] [Indexed: 06/08/2023]
Abstract
2-Phosphonobutane-1,2,4-tricarboxylic acid (PBTCA) is an antiscalant that is widely used in reverse osmosis (RO) systems. Because of its high concentration in RO concentrate, eutrophication risk and anti-precipitation properties may affect subsequent treatments, therefore treatment strategies are needed to eliminate such substances. In this study, PBTCA was degraded by ozonation. The results show that PBTCA reacted with ozone molecules and hydroxyl radicals, with second-order rate constants of (0.12 ± 0.002) and (7.83 ± 1.51) × 108 L mol-1 s-1, respectively. The phosphorus in PBTCA (PP) was transformed into organic phosphorus except for PBTCA (PO), and inorganic phosphorus (PI); PO was further transformed into PI. The changes in the concentrations of these phosphorus forms were investigated by model simulation. Simulation showed that the rate of PP transformation into PO was 5.5 times higher than that into PI. PBTCA was ozonated much faster at alkaline pH than at acidic pH. This is ascribed to different amounts of ozone molecules and hydroxyl radicals, and their different reaction rates with PBTCA. Furthermore, anti-precipitation property was reduced during ozonation, as shown by the amounts and morphology changes of the precipitates. PBTCA concentration for 50% anti-precipitation (AP50) did not change during ozonation, indicating that the transformation products generated during ozonation did not have anti-precipitation effects. Phosphorus in PBTCA was removed by ozonation-coagulation treatment. Total phosphorus and inorganic phosphorus were removed efficiently by using ferric chloride as a coagulant. The coagulants tended to bind with inorganic phosphorus to form flocs. Meanwhile, flocs were more easily to aggregate and precipitate as anti-precipitation effect was gradually removed, thus more phosphorus was removed. A combination of ozonation and coagulation removed PBTCA effectively and simultaneously reduced its anti-precipitation property and phosphorus.
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Affiliation(s)
- Zi-Bin Xu
- Environmental Simulation and Pollution Control State Key Joint Laboratory, State Environmental Protection Key Laboratory of Microorganism Application and Risk Control (SMARC), School of Environment, Tsinghua University, Beijing, 100084, People's Republic of China
| | - Wen-Long Wang
- Environmental Simulation and Pollution Control State Key Joint Laboratory, State Environmental Protection Key Laboratory of Microorganism Application and Risk Control (SMARC), School of Environment, Tsinghua University, Beijing, 100084, People's Republic of China; Shenzhen Laboratory of Microorganism Application and Risk Control, Guangdong Provincial Engineering Research Center for Urban Water Recycling and Environmental Safety, Graduate School at Shenzhen, Tsinghua University, Shenzhen, 518055, People's Republic of China
| | - Nan Huang
- Environmental Simulation and Pollution Control State Key Joint Laboratory, State Environmental Protection Key Laboratory of Microorganism Application and Risk Control (SMARC), School of Environment, Tsinghua University, Beijing, 100084, People's Republic of China
| | - Qian-Yuan Wu
- Shenzhen Laboratory of Microorganism Application and Risk Control, Guangdong Provincial Engineering Research Center for Urban Water Recycling and Environmental Safety, Graduate School at Shenzhen, Tsinghua University, Shenzhen, 518055, People's Republic of China.
| | - Min-Yong Lee
- Environmental Simulation and Pollution Control State Key Joint Laboratory, State Environmental Protection Key Laboratory of Microorganism Application and Risk Control (SMARC), School of Environment, Tsinghua University, Beijing, 100084, People's Republic of China
| | - Hong-Ying Hu
- Environmental Simulation and Pollution Control State Key Joint Laboratory, State Environmental Protection Key Laboratory of Microorganism Application and Risk Control (SMARC), School of Environment, Tsinghua University, Beijing, 100084, People's Republic of China; Shenzhen Environmental Science and New Energy Technology Engineering Laboratory, Tsinghua-Berkeley Shenzhen Institute, Shenzhen, 518055, People's Republic of China.
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Shahid MK, Pyo M, Choi YG. Inorganic fouling control in reverse osmosis wastewater reclamation by purging carbon dioxide. Environ Sci Pollut Res Int 2019; 26:1094-1102. [PMID: 28432627 DOI: 10.1007/s11356-017-9008-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Accepted: 04/07/2017] [Indexed: 06/07/2023]
Abstract
Inorganic fouling on the membrane surface is one of the major prevalent issues affecting the performance and cost of reverse osmosis system. Chemical dosage is a widely adopted method for the inhibition of inorganic scale on the membrane surface. In this study, CO2 was used to control inorganic scale formation on surface of reverse osmosis (RO) membrane in wastewater reclamation. The pH of influent could be lowered by purging CO2. It caused an increase in solubility of inorganic salts in water resulting in discharge of principle ions in concentrate stream. A pilot plant study was conducted with four different RO modules including control, with dosage of antiscalant, with purging CO2 and with co-addition of antiscalant and CO2. The effectiveness of CO2 purging was assessed on the basis of operational analysis, in-line analysis and morphological results. Ryznar stability index was used to determine the scaling potential of system. The examined data indicated that CO2 purging was successful to inhibit scale formation on the membrane surface. Moreover, CO2 was found more eco-friendly than antiscalant, as no by-products were generated in concentrate stream.
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Affiliation(s)
- Muhammad Kashif Shahid
- Department of Environmental Engineering, Daegu University, Gyeongsan, 712-714, Republic of Korea
| | - Minsu Pyo
- Department of Environmental Engineering, Daegu University, Gyeongsan, 712-714, Republic of Korea
| | - Young-Gyun Choi
- Department of Environmental Engineering, Daegu University, Gyeongsan, 712-714, Republic of Korea.
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