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Li W, Dong C, Hao Z, Wu X, Ding D, Duan J. The effectiveness and feasibility of ball-milled powdered activated carbon (BPAC) for removal of organic pesticides in conventional drinking water treatment process. Chemosphere 2024; 359:142229. [PMID: 38723688 DOI: 10.1016/j.chemosphere.2024.142229] [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] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2024] [Revised: 04/19/2024] [Accepted: 05/01/2024] [Indexed: 05/14/2024]
Abstract
In the conventional drinking water treatment process (CDWTP), powdered activated carbon (PAC) is commonly used for removing organic pesticides, or other organic contaminants. However, the hydraulic retention time (HRT) in CDWTP is insufficient for fulfilling PAC adsorption equilibrium to realize its full capacity. This study examined the adsorption kinetics, adsorption thermal dynamics, and removal efficiency for six organic pesticides using the ball-milled PAC (BPAC) with varying particle sizes in CDWTP. Based on the experiments with the pesticides of atrazine, diazinon, dimethoate, fenitrothion, isoproturon and thiometon, the results indicated that as the particle size reduced from around 38 μm for the commercial PAC to 1 μm for the BPAC, the adsorption rates for hydrophobic pesticides increased up to twentyfold. Diffusional adsorption from the bulk solution to the external PAC surface is the most likely predominant mechanism. This could allow a sufficient pesticides' adsorption within the limited HRT and to achieve a great depth removal of these toxic compounds. However, the addition of BPAC with a diameter of 1 μm was observed to significantly increase residual particles in treated water after the conventional treatment process. With a further systematic evaluation of both adsorption rate and particle penetration, a particle size of around 6 μm BPAC was considered a practical compromise between the adsorption rate and particle penetration for real application. Results from five surface waters of different water quality indicated that, compared to commercial PAC, application of 6 μm BPAC could achieve up to a 75% reduction in adsorbent dosage while maintaining around the same pesticide removal efficiencies. Additionally, thermodynamic analyses suggest that adsorption of these pesticides could be enthalpically or entropically driven depending on the degree of pesticide hydrophobicity.
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Affiliation(s)
- Wei Li
- Key Laboratory of Northwest Water Resources, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, 13 Yanta Road, Xi'an, 710055, China.
| | - Congjian Dong
- Key Laboratory of Northwest Water Resources, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, 13 Yanta Road, Xi'an, 710055, China
| | - Zijing Hao
- Key Laboratory of Northwest Water Resources, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, 13 Yanta Road, Xi'an, 710055, China
| | - Xinyi Wu
- Key Laboratory of Northwest Water Resources, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, 13 Yanta Road, Xi'an, 710055, China
| | - Donghai Ding
- College of Materials Science and Engineering, Xi'an University of Architecture and Technology, 13 Yanta Road, Xi'an, 710055, China
| | - Jinming Duan
- Centre for Water Management and Reuse, UniSA STEM, University of South Australia, Mawson Lakes Campus, SA, 5095, Australia.
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Yang C, Shen X, Shi X, Cui Z, Nan J, Lu H, Li J, Huang Q. Impact of submerged macrophytes on growth and 2-MIB release risk of Pseudanabaena sp.: From field monitoringa to cultural experiments. J Hazard Mater 2023; 442:130052. [PMID: 36182878 DOI: 10.1016/j.jhazmat.2022.130052] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [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: 07/06/2022] [Revised: 09/20/2022] [Accepted: 09/21/2022] [Indexed: 06/16/2023]
Abstract
The off-flavor compound 2-methylisoborneol (2-MIB) is generally associated with the proliferation and metabolism of filamentous cyanobacteria in shallow freshwater ecosystems. Here field monitoring in East Taihu Lake from July to October 2021, along with cultural experiments, was conducted to determine the impact of submerged macrophytes on the growth and 2-MIB production of filamentous cyanobacteria. Pseudanabaena sp. was identified as the 2-MIB producer with the highest detection rate (100%) and correlation coefficient (R=0.68, p < 0.001). The 2-MIB concentration and algal growth in the macrophyte-dominated zones were markedly decreased compared with those in the phytoplankton-dominated zone. Five submerged macrophytes classified into flat-leaf type (Vallisneria natans and Potamogeton crispus) and thin-leaf type (Hydrilla verticillata, Ceratophyllum demersum, and Myriophyllum spicatum) exhibited strong inhibition effects against Pseudanabaena sp.: Overall inhibition efficiencies (IEs) of 92.7% ± 6.8% and 92.7% ± 8.4% for cell growth and 2-MIB production were achieved, respectively. Moreover, the thin-leaf macrophytes exhibited significant higher IEs for cell growth (94.0% vs. 84.7%) and 2-MIB production (99.4% vs. 82.6%) than the flat-leaf macrophytes and can be selected as pioneer species in controlling odor problems. Nutrient uptake, increasing water clarity, shading effects, and allelopathic effects of the submerged macrophytes were found to be the dominant inhibition mechanisms.
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Affiliation(s)
- Changtao Yang
- College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China; Research Center for Aquatic Ecology of East Taihu Lake, Suzhou 215200, China
| | - Xiaobing Shen
- Research Center for Aquatic Ecology of East Taihu Lake, Suzhou 215200, China; Bureau of Water Resource of Wujiang District, Suzhou 215228, China
| | - Xinyi Shi
- College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China; Research Center for Aquatic Ecology of East Taihu Lake, Suzhou 215200, China
| | - Zhijie Cui
- College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China
| | - Jing Nan
- College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China
| | - Haiming Lu
- Nanjing Hydraulic Research Institute, Nanjing 210029, China
| | - Jianhua Li
- College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China
| | - Qinghui Huang
- College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China; Key Laboratory of Yangtze River Water Environment, Ministry of Education of China, Tongji University, Shanghai 200092, China.
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Chen Y, Duan T, Li W, Zhang J, Dong Y, Zhou Y, Zhou Y. The effect of dissolved natural organic matter on adsorption of phenolic compounds on suspended sediments. Environ Technol 2022; 43:3366-3377. [PMID: 33886432 DOI: 10.1080/09593330.2021.1921054] [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: 02/26/2021] [Accepted: 04/10/2021] [Indexed: 06/12/2023]
Abstract
Phenolic compounds have caused different degrees of negative impacts in aquatic environment. Amino acids, humic acids and carbohydrates are the three dominant types of dissolved natural organic matter (DNOM) in natural water bodies. In this research, the influences of dissolved natural organic matter (DNOM) on the adsorption behaviors of phenol, 2,4-dichlorophenol (DCP) and 2,4,6-trichlorophenol (TCP) in Weihe River suspended sediment were studied by using DL-alanine, fulvic acid and glucose as the representatives of the three types of DNOM. The results of batch adsorption experiments showed that, without DNOM, Langmuir and Freundlich had good fitting effects on the three phenolic compounds and their maximum adsorption capacities were 21.580, 27.768 and 24.758 mg/kg respectively. The presence of amino acids increased adsorption capacities of the phenol and TCP on suspended sediments by approximately 13.84% and 11.56% respectively. The existence of fulvic acid and glucose positively affected the adsorption of phenol, DCP and TCP on suspended sediment. The isothermal adsorption in the coexistence of different DNOM were more consistent with the nonlinear adsorption. Other influence factors including pH, ionic strength and temperature can influence the adsorption behavior to different extents. The impact of dissolved natural organic matter (DNOM) on adsorption should be fully considered when mastering environmental migration and transformation behaviors of phenolic compounds in water-sediments environment.
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Affiliation(s)
- Yuyun Chen
- School of Water and Environment, Chang'an University, Xi'an, People's Republic of China
- Key Laboratory of Subsurface Hydrology and Ecology in Arid Areas, Ministry of Education, Xi'an, People's Republic of China
| | - Ting Duan
- School of Water and Environment, Chang'an University, Xi'an, People's Republic of China
| | - Wei Li
- School of Water and Environment, Chang'an University, Xi'an, People's Republic of China
| | - Junqin Zhang
- School of Water and Environment, Chang'an University, Xi'an, People's Republic of China
| | - Yanxia Dong
- School of Water and Environment, Chang'an University, Xi'an, People's Republic of China
| | - Yiqiang Zhou
- School of Water and Environment, Chang'an University, Xi'an, People's Republic of China
| | - Yifan Zhou
- School of Water and Environment, Chang'an University, Xi'an, People's Republic of China
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Pan L, Nakayama A, Matsui Y, Matsushita T, Shirasaki N. Desorption of micropollutant from superfine and normal powdered activated carbon in submerged-membrane system due to influent concentration change in the presence of natural organic matter: Experiments and two-component branched-pore kinetic model. Water Res 2022; 208:117872. [PMID: 34837808 DOI: 10.1016/j.watres.2021.117872] [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: 06/27/2021] [Revised: 10/17/2021] [Accepted: 11/13/2021] [Indexed: 06/13/2023]
Abstract
Submerged-membrane hybrid systems (SMHSs) that combine membrane filtration with powdered activated carbon (PAC) take advantage of PAC's ability to adsorb and remove contaminants dissolved in water. However, the risk of contaminant desorption due to temporal changes in the influent concentration of the contaminant has not been thoroughly explored. In this study, we used a SMHS with conventionally-sized PAC or superfine PAC (SPAC) to remove 2-methylisoborneol (MIB), a representative micropollutant, from water containing natural organic matter (NOM), with the goal of elucidating adsorption-desorption phenomena in the SMHS. We found that 20-40% of the MIB that adsorbed on PAC and SPAC while the influent was contaminated with MIB (6 h, contamination period) desorbed to the liquid phase within 6 h from the time that the MIB-containing influent was replaced by MIB-free influent (no-contamination period). The percentage of desorption during the no-contamination period increased with increasing MIB breakthrough concentration during the contamination period. These findings indicate that the PAC/SPAC in the SMHS should be replaced while the breakthrough concentration is low, not only to keep a high removal rate but also to decrease the desorption risk. SPAC is fast in removal by adsorption, but it is also fast in release by desorption. SPAC (median diameter: 0.94 µm) showed almost the same adsorption-desorption kinetics as PAC (12.1 µm) of a double dose. A two-component branched-pore diffusion model combined with an IAST (ideal adsorbed solution theory)-Freundlich isotherm was used to describe and analyze the adsorption-desorption of MIB. The diffusivity of MIB molecules in the pores of the activated carbon particles decreased markedly in a short period of time. This decrease, which was attributed to fouling of the activated carbon in the SMHS by coagulant-treated water containing NOM, not only reduced the rate of MIB removal during the contamination period but also hindered the rate of MIB desorption during the no-contamination period and thus prevented the effluent MIB concentration from becoming high. On the other hand, coagulation did not change the concentration of NOM that competes with MIB for adsorption sites.
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Affiliation(s)
- Long Pan
- Faculty of Engineering, Hokkaido University, N13W8, Sapporo 060-8628, Japan
| | - Akiko Nakayama
- Graduate School of Engineering, Hokkaido University, N13W8, Sapporo 060-8628, Japan
| | - Yoshihiko Matsui
- Faculty of Engineering, Hokkaido University, N13W8, Sapporo 060-8628, Japan.
| | - Taku Matsushita
- Faculty of Engineering, Hokkaido University, N13W8, Sapporo 060-8628, Japan
| | - Nobutaka Shirasaki
- Faculty of Engineering, Hokkaido University, N13W8, Sapporo 060-8628, Japan
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Wang Q, Mitchell RL, Hofman R, Yu J, Yang M, Rietveld LC, Zietzschmann F. How properties of low molecular weight model competitors impact organic micropollutant adsorption onto activated carbon at realistically asymmetric concentrations. Water Res 2021; 202:117443. [PMID: 34333298 DOI: 10.1016/j.watres.2021.117443] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [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: 04/07/2021] [Revised: 07/13/2021] [Accepted: 07/13/2021] [Indexed: 06/13/2023]
Abstract
Low molecular weight (LMW) dissolved organic matter (DOM) is the predominant competitor for adsorption sites against organic micropollutants (OMPs) in activated carbon adsorption. However, top-down approaches using highly complex mixtures of real water DOM do not allow to concisely examine the impacts of specific LMW DOM molecular properties on competitive adsorption. Therefore, we followed a bottom-up approach using fifteen model compounds (mDOM) to elucidate how important DOM characteristics, including hydrophobicity and unsaturated structures (ring, double/triple bond), impact competitiveness. Large concentration asymmetry (~500 μg DOC/μg OMP) made mDOM compounds, which were overall less preferentially adsorbed than OMPs, become competitive against OMPs and inhibit OMP adsorption kinetics by pre-occupation of adsorption sites. Our results revealed that both hydrophobicity interactions and π-interactions increased mDOM competitiveness, while π-interactions outweighed hydrophobic interactions. However, π-interactions could not be satisfactorily evaluated with a parameter such as specific ultraviolet absorbance (SUVA) due to interferences of carboxyl groups in aromatic mDOMs. Instead, mDOM adsorbability, described by mDOM adsorption capacity, proved to be a comprehensive indicator for mDOM competitiveness. To our knowledge, this is the first study that systematically clarifies the impacts of intricately interacting molecular properties on DOM adsorption and the related competition against OMP adsorption. DOM adsorbability may inspire a new fractionation, and assist the further isolation, identification and detailed characterization of LMW DOM competitors in real DOM-containing waters.
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Affiliation(s)
- Qi Wang
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; Department of Water Management, Delft University of Technology, PO Box 5048, 2600 GA, Delft, the Netherland; University of the Chinese Academy of Sciences, Beijing 100049, China
| | - Raja-Louisa Mitchell
- Chair of Water Quality Control, Technische Universität Berlin, KF4, Str. des 17. Juni 135, Berlin 10623, Germany
| | - Roberta Hofman
- KWR Watercycle Research Institute, Nieuwegein 3433PE, the Netherland
| | - Jianwei Yu
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of the Chinese Academy of Sciences, Beijing 100049, China.
| | - Min Yang
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of the Chinese Academy of Sciences, Beijing 100049, China
| | - Luuk C Rietveld
- Department of Water Management, Delft University of Technology, PO Box 5048, 2600 GA, Delft, the Netherland
| | - Frederik Zietzschmann
- Department of Water Management, Delft University of Technology, PO Box 5048, 2600 GA, Delft, the Netherland; Chair of Water Quality Control, Technische Universität Berlin, KF4, Str. des 17. Juni 135, Berlin 10623, Germany; Berliner Wasserbetriebe, Motardstr. 35, Berlin 13629, Germany
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Guo X, Zang P, Li Y, Bi D. TiO2-Powdered Activated Carbon (TiO2/PAC) for Removal and Photocatalytic Properties of 2-Methylisoborneol (2-MIB) in Water. Water 2021; 13:1622. [DOI: 10.3390/w13121622] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
2-methylisoborneol (2-MIB) is a common taste and odor compound caused by off-flavor secondary metabolites, which represents one of the greatest challenges for drinking water utilities worldwide. A TiO2-coated activated carbon (TiO2/PAC) has been synthesized using the sol-gel method. A new TiO2/PAC photocatalyst has been successfully employed in photodegradation of 2-MIB under UV light irradiation. In addition, the combined results of XRD, SEM-EDX, FTIR and UV-Vis suggested that the nano-TiO2 had been successfully loaded on the surface of PAC. Experimental results of 2-MIB removal indicated that the adsorption capacities of PAC for 2-MIB were higher than that of TiO2/PAC. However, in the natural organic matter (NOM) bearing water, the removal efficiency of 2-MIB by TiO2/PAC and PAC were 97.8% and 65.4%, respectively, under UV light irradiation. Moreover, it was shown that the presence of NOMs had a distinct effect on the removal of MIB by TiO2/PAC and PAC. In addition, a simplified equivalent background compound (SEBC) model could not only be used to describe the competitive adsorption of MIB and NOM, but also represent the photocatalytic process. In comparison to other related studies, there are a few novel composite photocatalysts that could efficiently and rapidly remove MIB by the combination of adsorption and photocatalysis.
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