1
|
Ma W, Patel SK, Marcos Hernández M, Wang X, Zhou X, Pan W, Shin Y, Villagrán D, Elimelech M. Rapid, Selective, and Chemical-Free Removal of Dissolved Silica from Water via Electrosorption: Feasibility and Mechanisms. Environ Sci Technol 2024; 58:947-959. [PMID: 38153969 DOI: 10.1021/acs.est.3c08067] [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] [Indexed: 12/30/2023]
Abstract
The unavoidable and detrimental formation of silica scale in engineered processes necessitates the urgent development of effective, economic, and sustainable strategies for dissolved silica removal from water. Herein, we demonstrate a rapid, chemical-free, and selective silica removal method using electrosorption. Specifically, we confirm the feasibility of exploiting local pH dynamics at the electrodes in flow-through electrosorption, achieved through a counterintuitive cell configuration design, to induce ionization and concomitant electrosorption of dissolved silica. In addition, to improve the feasibility of silica electrosorption under high-salinity solutions, we developed a silica-selective anode by functionalizing porous activated carbon cloths with aluminum hydroxide nanoparticles (Al(OH)3-p-ACC). The modification markedly enhances silica sorption capacity (2.8 vs 1.1 mgsilica ganode-1) and reduces the specific energy consumption (13.3 vs 19.8 kWh kgsilica-1). Notably, the modified electrode retains remarkable silica sorption capacity even in the presence of high concentrations of co-occurring ions (up to 100 mM NaCl). The mechanisms underlying the superior silica removal stability and selectivity with the Al(OH)3-p-ACC electrode are also elucidated, revealing a synergistic interaction involving outer-sphere and inner-sphere complexation between dissolved silica and Al(OH)3 nanoparticles on the electrodes. Moreover, we find that effective regeneration of the electrodes may be achieved by applying a reverse potential during discharge, although complete regeneration of the modified electrodes may necessitate alternative materials or process optimization. We recommend the adoption of feedwater-specific designs for the development of future silica-selective electrodes in electrosorption capable of meeting silica removal demands across a wide range of engineered systems.
Collapse
Affiliation(s)
- Wen Ma
- Department of Chemical and Environmental Engineering, Yale University, New Haven, Connecticut 06520, United States
- Department of Chemical and Biotechnology Engineering, Université de Sherbrooke, Sherbrooke, Quebec J1K 2R1, Canada
| | - Sohum K Patel
- Department of Chemical and Environmental Engineering, Yale University, New Haven, Connecticut 06520, United States
| | - Mariana Marcos Hernández
- Department of Chemistry and Biochemistry and Nanosystems Engineering Research Center for Nanotechnology-Enabled Water Treatment (NEWT), The University of Texas at El Paso, El Paso, Texas 79968, United States
| | - Xiaoxiong Wang
- Department of Chemical and Environmental Engineering, Yale University, New Haven, Connecticut 06520, United States
| | - Xuechen Zhou
- Department of Chemical and Environmental Engineering, Yale University, New Haven, Connecticut 06520, United States
| | - Weiyi Pan
- Department of Chemical and Environmental Engineering, Yale University, New Haven, Connecticut 06520, United States
| | - Yonguk Shin
- Department of Chemical and Environmental Engineering, Yale University, New Haven, Connecticut 06520, United States
| | - Dino Villagrán
- Department of Chemistry and Biochemistry and Nanosystems Engineering Research Center for Nanotechnology-Enabled Water Treatment (NEWT), The University of Texas at El Paso, El Paso, Texas 79968, United States
| | - Menachem Elimelech
- Department of Chemical and Environmental Engineering, Yale University, New Haven, Connecticut 06520, United States
- Nanosystems Engineering Research Center for Nanotechnology─Enabled Water Treatment (NEWT), Yale University, New Haven, Connecticut 06511, United States
| |
Collapse
|
2
|
Kaneda M, Dong D, Chen Y, Zhang X, Xue Y, Bryantsev VS, Elimelech M, Zhong M. Molecular Design of Functional Polymers for Silica Scale Inhibition. Environ Sci Technol 2024; 58:871-882. [PMID: 38150403 DOI: 10.1021/acs.est.3c06504] [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] [Indexed: 12/29/2023]
Abstract
Silica polymerization, which involves the condensation reaction of silicic acid, is a fundamental process with wide-ranging implications in biological systems, material synthesis, and scale formation. The formation of a silica-based scale poses significant technological challenges to energy-efficient operations in various industrial processes, including heat exchangers and water treatment membranes. Despite the common strategy of applying functional polymers for inhibiting silica polymerization, the underlying mechanisms of inhibition remain elusive. In this study, we synthesized a series of nitrogen-containing polymers as silica inhibitors and elucidated the role of their molecular structures in stabilizing silicic acids. Polymers with both charged amine and uncharged amide groups in their backbones exhibit superior inhibition performance, retaining up to 430 ppm of reactive silica intact for 8 h under neutral pH conditions. In contrast, monomers of these amine/amide-containing polymers as well as polymers containing only amine or amide functionalities present insignificant inhibition. Molecular dynamics simulations reveal strong binding between the deprotonated silicic acid and a polymer when the amine groups in the polymer are protonated. Notably, an extended chain conformation of the polymer is crucial to prevent proximity between the interacting monomeric silica species, thereby facilitating effective silica inhibition. Furthermore, the hydrophobic nature of alkyl segments in polymer chains disrupts the hydration shell around the polymer, resulting in enhanced binding with ionized silicic acid precursors compared to monomers. Our findings provide novel mechanistic insights into the stabilization of silicic acids with functional polymers, highlighting the molecular design principles of effective inhibitors for silica polymerization.
Collapse
Affiliation(s)
- Masashi Kaneda
- Department of Chemical and Environmental Engineering, Yale University, New Haven, Connecticut 06520, United States
| | - Dengpan Dong
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Yinan Chen
- Department of Chemical and Environmental Engineering, Yale University, New Haven, Connecticut 06520, United States
| | - Xiaowei Zhang
- Department of Chemical and Environmental Engineering, Yale University, New Haven, Connecticut 06520, United States
| | - Yazhen Xue
- Department of Chemical and Environmental Engineering, Yale University, New Haven, Connecticut 06520, United States
| | - Vyacheslav S Bryantsev
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Menachem Elimelech
- Department of Chemical and Environmental Engineering, Yale University, New Haven, Connecticut 06520, United States
| | - Mingjiang Zhong
- Department of Chemical and Environmental Engineering, Yale University, New Haven, Connecticut 06520, United States
- Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States
| |
Collapse
|
3
|
Abstract
Dissolved silica is a major concern for a variety of industrial processes owing to its tendency to form complex scales that severely deteriorate system performance. In this work, we present a pretreatment technology using a Joule-heated sponge to rapidly remove silica from saline waters through adsorption, thereby effectively mitigating silica scaling in subsequent membrane desalination processes. The adsorbent sponge is fabricated by functionalizing two-dimensional layered double hydroxide (LDH) nanosheets on a porous, conductive stainless-steel sponge. With the application of an external voltage of 4 V, the Joule-heated sponge achieves 85% silica removal and 95% sponge regeneration within 15 min, which is much more efficient than its counterpart without Joule-heating (360 min for silica adsorption and 90 min for sponge regeneration). Material characterization and reaction kinetics analysis reveal that electrostatic interactions and "memory effect"-induced intercalation are the primary mechanisms for silica removal by the LDH nanosheets. Moreover, Joule-heating reduces the boundary layer resistance on nanosheets and facilitates intraparticle diffusion of dissolved silica, thereby increasing silica removal kinetics. Joule-heating also enhances the release of silicate ions during the regeneration stage through exchange with the surrounding anions (OH- or CO32-), resulting in a more efficient sponge regeneration. Pretreatment of silica-rich feedwaters by the Joule-heated sponge effectively reduces reverse osmosis membrane scaling by amorphous silica scale, demonstrating great potential for silica scaling control in a broad range of engineered processes.
Collapse
Affiliation(s)
- Wen Ma
- Department of Chemical and Environmental Engineering Yale University, New Haven, Connecticut 06520, United States
- Nanosystems Engineering Research Center for Nanotechnology-Enabled Water Treatment (NEWT), Houston, Texas 77005, United States
| | - Xinglin Lu
- Department of Chemical and Environmental Engineering Yale University, New Haven, Connecticut 06520, United States
- Nanosystems Engineering Research Center for Nanotechnology-Enabled Water Treatment (NEWT), Houston, Texas 77005, United States
- CAS Key Laboratory of Urban Pollutant Conversion, Department of Environmental Science and Engineering, University of Science and Technology of China, Hefei 230026, China
| | - Yan-Fang Guan
- Department of Chemical and Environmental Engineering Yale University, New Haven, Connecticut 06520, United States
- Nanosystems Engineering Research Center for Nanotechnology-Enabled Water Treatment (NEWT), Houston, Texas 77005, United States
- CAS Key Laboratory of Urban Pollutant Conversion, Department of Environmental Science and Engineering, University of Science and Technology of China, Hefei 230026, China
| | - Menachem Elimelech
- Department of Chemical and Environmental Engineering Yale University, New Haven, Connecticut 06520, United States
- Nanosystems Engineering Research Center for Nanotechnology-Enabled Water Treatment (NEWT), Houston, Texas 77005, United States
| |
Collapse
|
4
|
Cheong C, Sakaguchi A, Sueki K, Ohata M. Evaluation of the Calibration Method for Accurate Analysis of Dissolved Silica by Continuous Flow Analysis. ANAL SCI 2020; 36:247-251. [PMID: 31564679 DOI: 10.2116/analsci.19p291] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
For accurately determining nutrients in seawater by continuous flow analysis (CFA), the characteristic of the calibration curve was examined in detail. Under absorbance below 0.8, the calibration curve and the bracketing methods showed more accurate results that the bias fell below 0.5%. The analytical results of dissolved silica in seawater from the nutrient maximum layer of the Pacific Ocean obtained by the proposed methods showed good agreement with those obtained by an ion exclusion chromatography postcolumn absorption spectrophotometry (IEC-postcolumn) and an ion exclusion chromatography isotope dilution ICP mass spectrometry (IEC-ID-ICP-MS). From the results, the analysis of nutrients in seawater could be accurately carried out by CFA with an expanded uncertainty of below 1% using both the calibration curve and the bracketing methods with an appropriate absorbance range.
Collapse
Affiliation(s)
- Chikako Cheong
- Graduate School of Life and Environmental Sciences, The University of Tsukuba.,National Metrology Institute of Japan (NMIJ), National Institute of Advanced Industrial Science and Technology (AIST)
| | - Aya Sakaguchi
- Graduate School of Life and Environmental Sciences, The University of Tsukuba
| | - Keisuke Sueki
- Graduate School of Life and Environmental Sciences, The University of Tsukuba
| | - Masaki Ohata
- National Metrology Institute of Japan (NMIJ), National Institute of Advanced Industrial Science and Technology (AIST)
| |
Collapse
|
5
|
McDowell WH, McDowell WG, Potter JD, Ramírez A. Nutrient export and elemental stoichiometry in an urban tropical river. Ecol Appl 2019; 29:e01839. [PMID: 30578700 DOI: 10.1002/eap.1839] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Accepted: 09/19/2018] [Indexed: 05/27/2023]
Abstract
Nutrient inputs to surface waters are particularly varied in urban areas, due to multiple nutrient sources and complex hydrologic pathways. Because of their close proximity to coastal waters, nutrient delivery from many urban areas can have profound impacts on coastal ecology. Relatively little is known about the temporal and spatial variability in stoichiometry of inorganic nutrients such as dissolved silica, nitrogen, and phosphorus (Si, N, and P) and dissolved organic matter in tropical urban environments. We examined nutrient stoichiometry of both inorganic nutrients and organic matter in an urban watershed in Puerto Rico served by municipal sanitary sewers and compared it to two nearby forested catchments using samples collected weekly from each river for 6 yr. Urbanization caused large increases in the concentration and flux of nitrogen and phosphorus (2- to 50-fold), but surprisingly little change in N:P ratio. Concentrations of almost all major ions and dissolved silica were also significantly higher in the urban river than the wildland rivers. Yield of dissolved organic carbon (DOC) was not increased dramatically by urbanization, but the composition of dissolved organic matter shifted toward N-rich material, with a larger increase in dissolved organic nitrogen (DON) than DOC. The molar ratio of DOC:DON was about 40 in rivers draining forested catchments but was only 10 in the urban river. Inclusion of Si in the assessment of urbanization's impacts reveals a large shift in the stoichiometry (Si:N and Si:P) of nutrient inputs. Because both Si concentrations and watershed exports are high in streams and rivers from many humid tropical catchments with siliceous bedrock, even the large increases in N and P exported from urban catchments result in delivery of Si, N, and P to coastal waters in stoichiometric ratios that are well in excess of the Si requirements of marine diatoms. Our data suggest that dissolved Si, often neglected in watershed biogeochemistry, should be included in studies of urban as well as less developed watersheds due to its potential significance for marine and lacustrine productivity.
Collapse
Affiliation(s)
- William H McDowell
- Department of Natural Resources and the Environment, University of New Hampshire Main Campus, Durham, New Hampshire, 03824, USA
| | - William G McDowell
- Department of Biology, Merrimack College, North Andover, Massachusetts, 01845, USA
| | - Jody D Potter
- Department of Natural Resources and the Environment, University of New Hampshire Main Campus, Durham, New Hampshire, 03824, USA
| | - Alonso Ramírez
- Department of Applied Ecology, North Carolina State University, Raleigh, North Carolina, 27695, USA
| |
Collapse
|
6
|
Pham ALT, Doyle FM, Sedlak DL. Kinetics and efficiency of H2O2 activation by iron-containing minerals and aquifer materials. Water Res 2012; 46:6454-62. [PMID: 23047055 PMCID: PMC3891917 DOI: 10.1016/j.watres.2012.09.020] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2012] [Revised: 09/07/2012] [Accepted: 09/09/2012] [Indexed: 05/22/2023]
Abstract
To gain insight into factors that control H(2)O(2) persistence and ·OH yield in H(2)O(2)-based in situ chemical oxidation systems, the decomposition of H(2)O(2) and transformation of phenol were investigated in the presence of iron-containing minerals and aquifer materials. Under conditions expected during remediation of soil and groundwater, the stoichiometric efficiency, defined as the amount of phenol transformed per mole of H(2)O(2) decomposed, varied from 0.005 to 0.28%. Among the iron-containing minerals, iron oxides were 2-10 times less efficient in transforming phenol than iron-containing clays and synthetic iron-containing catalysts. In both iron-containing mineral and aquifer materials systems, the stoichiometric efficiency was inversely correlated with the rate of H(2)O(2) decomposition. In aquifer materials systems, the stoichiometric efficiency was also inversely correlated with the Mn content, consistent with the fact that the decomposition of H(2)O(2) on manganese oxides does not produce ·OH. Removal of iron and manganese oxide coatings from the surface of aquifer materials by extraction with citrate-bicarbonate-dithionite slowed the rate of H(2)O(2) decomposition on aquifer materials and increased the stoichiometric efficiency. In addition, the presence of 2 mM of dissolved SiO(2) slowed the rate of H(2)O(2) decomposition on aquifer materials by over 80% without affecting the stoichiometric efficiency.
Collapse
Affiliation(s)
- Anh Le-Tuan Pham
- Department of Civil and Environmental Engineering, University of California at Berkeley Berkeley, California 94720
| | - Fiona M. Doyle
- Department of Materials Science and Engineering, University of California at Berkeley Berkeley, California 94720
- Address correspondence to either author: Fiona Doyle, Department of Materials Science and Engineering, 320 McLaughlin Hall, University of California, Berkeley, Berkeley CA 94720-1700. Phone: +1-510-642-5771. Fax: +1-510-642-9178. David Sedlak, Department of Civil and Environmental Engineering, 657 Davis Hall, University of California, Berkeley, Berkeley CA 94720-1710. Phone: +1-510-643-0256. Fax: +1-510-642-7483.
| | - David L. Sedlak
- Department of Civil and Environmental Engineering, University of California at Berkeley Berkeley, California 94720
- Address correspondence to either author: Fiona Doyle, Department of Materials Science and Engineering, 320 McLaughlin Hall, University of California, Berkeley, Berkeley CA 94720-1700. Phone: +1-510-642-5771. Fax: +1-510-642-9178. David Sedlak, Department of Civil and Environmental Engineering, 657 Davis Hall, University of California, Berkeley, Berkeley CA 94720-1710. Phone: +1-510-643-0256. Fax: +1-510-642-7483.
| |
Collapse
|