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Zhang Y, Chen Z, Shi Y, Ma Q, Mao H, Li Y, Wang H, Zhang Y. Revealing the sorption mechanisms of carbamazepine on pristine and aged microplastics with extended DLVO theory. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 874:162480. [PMID: 36858211 DOI: 10.1016/j.scitotenv.2023.162480] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/26/2022] [Revised: 02/14/2023] [Accepted: 02/22/2023] [Indexed: 06/18/2023]
Abstract
The co-occurrence of microplastics (MPs) and organic contaminants in aquatic environment can complexify their environmental fate via sorption interactions, especially when the properties of MPs can even vary due to the aging effect. Thus, quantitatively clarifying the sorption mechanisms is required to understand their environmental impacts. This study selected popularly occurring carbamazepine (CBZ) and four types of MPs as model systems, including polyethylene, polyvinyl chloride, polyethylene terephthalate and polystyrene in their pristine and aged forms, to investigate the sorption isotherms, kinetics, and desorption. The variation of MPs during the aging process were analyzed with scanning electron microscopy, contact angle, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. It was found that the aging process elevated the sorption capacity and intensified the desorption hysteresis of CBZ on MPs via increasing the surface roughness, decreasing the particle size, and altering the surficial chemistry of all MPs. The extended Derjaguin-Landau-Verwey-Overbeek (XDLVO) theory was innovatively applied hereby to calculate the interfacial free energies and revealed that the hydrophobic interaction was significantly lessened after aging for all MPs with the slightly enhanced van der Waals interaction. Then the total interfacial free energies were dropped down for all MPs, which resulted in their declined specific sorption capacity. This work reveals the sorption mechanisms of CBZ on pristine and aged MPs with XDLVO and provides a useful reference to study the sorption of other neutral organics onto MPs.
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Affiliation(s)
- Yunhai Zhang
- School of Environmental Science and Engineering, Nanjing Tech University, Nanjing 211816, People's Republic of China
| | - Zihao Chen
- School of Environmental Science and Engineering, Nanjing Tech University, Nanjing 211816, People's Republic of China
| | - Yuexiao Shi
- School of Environmental Science and Engineering, Nanjing Tech University, Nanjing 211816, People's Republic of China
| | - Qing Ma
- School of Environmental Science and Engineering, Nanjing Tech University, Nanjing 211816, People's Republic of China
| | - Haoran Mao
- School of Environmental Science and Engineering, Nanjing Tech University, Nanjing 211816, People's Republic of China
| | - Ying Li
- School of Environmental Science and Engineering, Nanjing Tech University, Nanjing 211816, People's Republic of China
| | - Hao Wang
- School of Environmental Science and Engineering, Nanjing Tech University, Nanjing 211816, People's Republic of China
| | - Yongjun Zhang
- School of Environmental Science and Engineering, Nanjing Tech University, Nanjing 211816, People's Republic of China.
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Separation of plastic wastes using froth flotation - An overview. Adv Colloid Interface Sci 2022; 308:102769. [PMID: 36116142 DOI: 10.1016/j.cis.2022.102769] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Revised: 08/29/2022] [Accepted: 08/30/2022] [Indexed: 11/22/2022]
Abstract
Despite various initiatives and efforts, plastic solid waste (PSW) has become a major global problem due to decades of relentless use of plastics. Since non-biodegradable plastics can persist in the environment for hundreds of years, threatening animal and human life, discarding them into the environment is not a viable option. Plastic recycling is a critical research area that requires urgent attention since less than 10% of the seven billion tons of globally generated plastic waste has been recycled so far. With recent technological developments, it is now possible to recycle many types of PSW using a variety of methods. This review provides an overview of the froth flotation technology that is currently being researched for PSW recycling. Fundamental working principles, the current state of the development, and limitations of this technique are reviewed. It is suggested that froth flotation with continuous development has tremendous potential to result in a more efficient and environmentally friendly approach to PSW recycling.
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Wang Z, Jiang H, Zhang Y, Bian K, Wang H, Wang C. Stepwise flotation separation of WEEE plastics by polymeric aluminum chloride towards source control of microplastics. WASTE MANAGEMENT (NEW YORK, N.Y.) 2022; 149:1-10. [PMID: 35689973 DOI: 10.1016/j.wasman.2022.05.029] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2022] [Revised: 05/07/2022] [Accepted: 05/31/2022] [Indexed: 06/15/2023]
Abstract
The mismanagement of waste electrical and electronic equipment (WEEE) resulted in numerous discarded plastics in the natural environment, and these waste plastics might experience aging, breaking, and migration, which becomes a crucial microplastic source. Sustainable management of WEEE plastics presents a considerable opportunity for resource recovery and microplastic pollution prevention. Flotation separation is a significant process of mechanical recycling, while most flotation methods can only deal with binary plastic mixtures. In this work, an advanced, stepwise, and sustainable flotation method was advocated to separate multi-plastics by polymeric aluminum chloride (PAC) modification. The abundant hydrophilic groups and environmental friendliness of PAC prompted us to further investigate the wetting effect. PAC had varied hydrophilization effects on acrylonitrile butadiene styrene (ABS) and polystyrene (PS) surfaces, but polyethylene terephthalate (PET) retained hydrophobicity. Treatment conditions, including PAC dosage, temperature, time, and pH were optimized. 100% of PET could be purified after primary separation, and the purities of ABS and PS could reach 100% and 97.4% after secondary separation, respectively. The strength of the interaction was determined by the different surface potentials and functional groups. In PAC solution, long-chain molecules or ions might interact with plastic surfaces electrostatically, and Al3+ could bridge long-chain molecules and plastic surfaces, thereby strengthening the polymer hydrophilicity. We further improved the PAC treatment process, and the reuse of PAC reduced modifier usage to 84.4 g/ton waste plastics, which was cost-effective in industrial applications. A preliminary evaluation of the energy consumption and environmental impact indicated that PAC treatment was superior to other modification methods. This work is an initial attempt at the stepwise separation of waste plastic and shows promising prospects for recycling plastic waste.
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Affiliation(s)
- Zhiyi Wang
- College of Chemistry and Chemical Engineering, Central South University, Changsha, 410083 Hunan, PR China
| | - Hongru Jiang
- College of Chemistry and Chemical Engineering, Central South University, Changsha, 410083 Hunan, PR China
| | - Yingshuang Zhang
- College of Chemistry and Chemical Engineering, Central South University, Changsha, 410083 Hunan, PR China
| | - Kai Bian
- College of Chemistry and Chemical Engineering, Central South University, Changsha, 410083 Hunan, PR China
| | - Hui Wang
- College of Chemistry and Chemical Engineering, Central South University, Changsha, 410083 Hunan, PR China.
| | - Chongqing Wang
- School of Chemical Engineering and Energy, Zhengzhou University, Zhengzhou 450001, PR China.
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Zhao Y, Han F, Guo L, Zhang J, Zhang H, Abdelaziz IIM, Ghazali KH. Flotation separation of poly (ethylene terephthalate and vinyl chloride) mixtures based on clean corona modification: Optimization using response surface methodology. WASTE MANAGEMENT (NEW YORK, N.Y.) 2021; 136:184-194. [PMID: 34689097 DOI: 10.1016/j.wasman.2021.10.018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Revised: 09/17/2021] [Accepted: 10/12/2021] [Indexed: 06/13/2023]
Abstract
Postconsumer polyethylene terephthalate (PET) has potential applications in many areas of manufacturing, but contamination by hazardous polyvinyl chloride (PVC) in common waste streams can reduce its recyclable value. Separating collected PET-PVC mixtures before recycling remains very challenging because of the similar physicochemical properties of PET and PVC. Herein, we describe a novel flotation process with corona modification pretreatment to facilitate the separation of PET-PVC mixtures. Through water contact angle, surface free energy, X-ray photoelectron and FT-IR characterization, we found that polar hydroxyl groups can be more easily introduced on the PVC surface than on the PET surface induced by corona modification. This selective wetting can suppress the floatability of PVC, leading to the separation of PET as floating product. A reliable mechanism including two different hydrogen-abstraction pathways was established. Response surface methodology consisting of Plackett-Burman and Box-Behnken designs was adopted for optimization of the combined process, and control parameters were solved based on high-quality prediction models, with fitting from significant variables and interactions. For physical or chemical circulation strategies with PET purity prioritization, the validated purity of the product reached 96.05% at a 626 W corona power, 5.42 m/min passing speed, 24.78 mg/L frother concentration and 286 L/h air flow rate. For the energy recuperation strategy with PET recovery prioritization, the factual recovery reached 98.08% under a 601 W corona power, 6.04 m/min passing speed, 27.55 mg/L frother concentration and 184 L/h air flow rate. The current work provides technological insights into the cleaner disposal of waste plastics.
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Affiliation(s)
- Yue Zhao
- Shaanxi Key Laboratory of Disaster Monitoring & Mechanism Simulating, College of Geography and Environment, Baoji University of Arts and Sciences, Baoji 721013, China.
| | - Fengrong Han
- College of Engineering, Universiti Malaysia Pahang, Pekan 26600, Malaysia
| | - Linyi Guo
- Shaanxi Key Laboratory of Disaster Monitoring & Mechanism Simulating, College of Geography and Environment, Baoji University of Arts and Sciences, Baoji 721013, China
| | - Jun Zhang
- Shaanxi Key Laboratory of Disaster Monitoring & Mechanism Simulating, College of Geography and Environment, Baoji University of Arts and Sciences, Baoji 721013, China
| | - Haidong Zhang
- Shaanxi Key Laboratory of Disaster Monitoring & Mechanism Simulating, College of Geography and Environment, Baoji University of Arts and Sciences, Baoji 721013, China
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Zhao J, Song Q, He Q, Dionysiou DD, Wu F, Feng Y, Zhang X. Fabrication of Bi 1.81MnNbO 6.72/sulfite system for efficient degradation of chlortetracycline. CHEMOSPHERE 2021; 268:129269. [PMID: 33360936 DOI: 10.1016/j.chemosphere.2020.129269] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Revised: 11/13/2020] [Accepted: 12/07/2020] [Indexed: 06/12/2023]
Abstract
The design of eco-friendly Bi1.81MnNbO6.72/sulfite system for efficient degradation of chlortetracycline was achieved. The feasibility of synthesizing Bi1.81MnNbO6.72 by hydrothermal method was determined by X-ray diffraction. The magnetic test suggested that Bi1.81MnNbO6.72 possessed paramagnetic properties, indicating unpaired electrons were present. Scanning electron microscope and transmission electron microscopy images revealed that Bi1.81MnNbO6.72 octahedra exhibited exposed [1,1,1] crystal plane containing high density of Bi, Mn and Nb metal atoms. Large numbers of metal atoms will facilitate heterogeneous catalytic process. In a batch system with aeration, Bi1.81MnNbO6.72 could be used as sulfite activator for the disposal of chlortetracycline. The reaction kinetics of the degradation process conformed to the pseudo-second-order kinetic model. In Bi1.81MnNbO6.72/sulfite process, initial pH, Bi1.81MnNbO6.72 dosage, sulfite and chlortetracycline concentrations, as well as inorganic salt ions had great effect on chlortetracycline degradation. Under optimal conditions, the efficiency of Bi1.81MnNbO6.72/sulfite system for degradation of chlortetracycline could reach 76.2%. Moreover, Mn (II) plays a key role in the initiation of the catalytic reaction in Bi1.81MnNbO6.72/sulfite process. Generated SO3●‒ could act as main reactive species in Bi1.81MnNbO6.72/sulfite process, while HO● was also involved. Three new degradation products were detected by UHPLC/MS/MS and the possible degradation pathways in this system were proposed. Based on this, we believe that Bi1.81MnNbO6.72/sulfite is a type of process for degradation of organic contaminants with research significance and application prospects.
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Affiliation(s)
- Jie Zhao
- Department of Applied Chemistry, Xi'an University of Technology, 5 Jinhua South Road, Xi'an, Shaanxi, 710048, PR China.
| | - Qiang Song
- Department of Applied Chemistry, Xi'an University of Technology, 5 Jinhua South Road, Xi'an, Shaanxi, 710048, PR China
| | - Qiang He
- Technical Center, Xi'an Customs District, Shaanxi, 710068, PR China
| | - Dionysios D Dionysiou
- Environmental Engineering and Science Program, Department of Chemical and Environmental Engineering (ChEE), University of Cincinnati, Cincinnati, OH, 45221, United States
| | - Fei Wu
- Department of Applied Chemistry, Xi'an University of Technology, 5 Jinhua South Road, Xi'an, Shaanxi, 710048, PR China
| | - Yawei Feng
- Department of Applied Chemistry, Xi'an University of Technology, 5 Jinhua South Road, Xi'an, Shaanxi, 710048, PR China
| | - Xinying Zhang
- Department of Applied Chemistry, Xi'an University of Technology, 5 Jinhua South Road, Xi'an, Shaanxi, 710048, PR China
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Ma J, Niu X, Zhang D, Lu L, Ye X, Deng W, Li Y, Lin Z. High levels of microplastic pollution in aquaculture water of fish ponds in the Pearl River Estuary of Guangzhou, China. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 744:140679. [PMID: 32755771 DOI: 10.1016/j.scitotenv.2020.140679] [Citation(s) in RCA: 52] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2020] [Revised: 06/28/2020] [Accepted: 06/30/2020] [Indexed: 06/11/2023]
Abstract
Microplastics (MPs) have caused great concern worldwide recently due to their ubiquity in the aquatic environment. The current knowledge on the occurrence of MPs in aquaculture fish ponds in a typical estuary system remains meagre. This study investigated the abundance and characteristics (shape, color, size and composition) of MPs in aquaculture water and pond influents in the Pearl River Estuary of Guangzhou, China, using an improved separation method. The bulk sampling and improved separation method by the combination of ethanol and polyaluminum chloride (PAC) significantly increased the MP separation efficiency, especially for particles with size less than <333 μm. The investigation results showed that MPs were detected in all water samples of fish ponds at two experimental stations with abundances of 10.3-60.5 particles/L (S1) and 33.0-87.5 particles/L (S2), respectively. Moreover, the average abundance of MPs in aquaculture water (42.1 particles/L) exhibited higher value than that in pond influents (32.1 particles/L). Most of MPs were colored and fibrous in appearance. MPs with the size range of <1000 μm (56.3-87.7%) prevailed in aquaculture water. MPs with size <333 μm that usually ignored in most studies were detected with percentage of 43.7% at S1station and 33.2% at S2 station, respectively. The small-sized MPs (<100 μm) in aquaculture water (23.7% at S1 station and 14.6% at S2 station) were more abundant than those in pond influents (7.2% at S1 station and 2.5% at S2 station). The main composition of MPs was polypropylene (PP) and polyethylene (PE). These findings indicated a high level of MP pollution in aquaculture fish ponds. The MPs originated from the Pearl River Estuary were accumulated in aquaculture fish ponds. This study provides an insight into MP pollution in aquaculture fish ponds at a typical estuarine system and highlights the load of MPs in the pond influents.
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Affiliation(s)
- Jinling Ma
- School of Environment and Energy, South China University of Technology, Guangzhou 510006, PR China
| | - Xiaojun Niu
- School of Environment and Energy, South China University of Technology, Guangzhou 510006, PR China; School of Environmental Science and Engineering, Guangdong University of Petrochemical Technology, Maoming 525000, China; Guangdong Provincial Key Laboratory of Atmospheric Environment and Pollution Control, South China University of Technology, Guangzhou Higher Education Mega Centre, Guangzhou 510006, PR China; The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, South China University of Technology, Guangzhou Higher Education Mega Centre, Guangzhou 510006, PR China.
| | - Dongqing Zhang
- School of Environmental Science and Engineering, Guangdong University of Petrochemical Technology, Maoming 525000, China.
| | - Lu Lu
- School of Environment and Energy, South China University of Technology, Guangzhou 510006, PR China
| | - Xingyao Ye
- School of Environment and Energy, South China University of Technology, Guangzhou 510006, PR China
| | - Wangde Deng
- School of Environment and Energy, South China University of Technology, Guangzhou 510006, PR China
| | - Yankun Li
- School of Environment and Energy, South China University of Technology, Guangzhou 510006, PR China
| | - Zhang Lin
- School of Environment and Energy, South China University of Technology, Guangzhou 510006, PR China
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Liu T, Miao D, Liu G, Wei Q, Zhou K, Yu Z, Ma L. A novel gradient current density output mode for effective electrochemical oxidative degradation of dye wastewater by boron-doped diamond (BDD) anode. WATER SCIENCE AND TECHNOLOGY : A JOURNAL OF THE INTERNATIONAL ASSOCIATION ON WATER POLLUTION RESEARCH 2020; 82:2085-2097. [PMID: 33263586 DOI: 10.2166/wst.2020.473] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
In order to solve the problems of high energy consumption and low current efficiency in electrochemical oxidation (EO) degradation under the traditional constant output process (COP), a gradient output process (GOP) of current density is proposed in this paper. That is, the current density is gradually reduced in a fixed degradation time, and the Reactive Blue 19 simulated dye wastewater was used as the degradation target. The general applicability of the process was further confirmed by studying the optimal gradient current density output parameters, the dye concentration, electrolyte concentration and other dye compounds with different molecular structures. The corresponding results show that the chemical oxygen demand (COD) removal (78%) and the color removal (100%) under the GOP are similar to those in the COP, and the overall energy consumption is reduced by about 50% compared with that in the traditional constant current mode. Moreover, the current efficiency in the middle and late stages of EO process has increased by 8.6 times compared with COP.
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Affiliation(s)
- Ting Liu
- State Key Laboratory of Powder Metallurgy, School of Materials Science and Engineering, Central South University, Changsha 410083, China E-mail: ; The authors contributed equally to this work and should be considered co-first authors
| | - Dongtian Miao
- State Key Laboratory of Powder Metallurgy, School of Materials Science and Engineering, Central South University, Changsha 410083, China E-mail: ; The authors contributed equally to this work and should be considered co-first authors
| | - Guoshuai Liu
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Qiuping Wei
- State Key Laboratory of Powder Metallurgy, School of Materials Science and Engineering, Central South University, Changsha 410083, China E-mail:
| | - Kechao Zhou
- State Key Laboratory of Powder Metallurgy, School of Materials Science and Engineering, Central South University, Changsha 410083, China E-mail:
| | - Zhiming Yu
- State Key Laboratory of Powder Metallurgy, School of Materials Science and Engineering, Central South University, Changsha 410083, China E-mail:
| | - Li Ma
- State Key Laboratory of Powder Metallurgy, School of Materials Science and Engineering, Central South University, Changsha 410083, China E-mail:
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Jiang H, Zhang Y, Wang H. Surface Reactions in Selective Modification: The Prerequisite for Plastic Flotation. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:9742-9756. [PMID: 32659077 DOI: 10.1021/acs.est.9b07861] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Improper disposal of waste plastic has caused much environmental pollution, but plastic recycling can reduce the amount of new and residual waste plastic in the environment through source control. Plastic flotation can separate waste plastics with similar physical and chemical properties, which suggests its promising application in plastic recycling. With the help of the different hydrophilicities waste plastic can be separated by flotation, and hydrophilization can be accomplished by surface modifications. However, no systematic studies addressing these surface reactions have been published yet, and such modifications are a prerequisite for plastic flotation. In this critical review, we not only summarize the various modification mechanisms, including physical regulation, surface oxidation, surface degradation, dechlorination, and coating, but also have reasonably added additional information for some reactions covering surface reconstruction, plastic degradation, polymer stability, wastewater treatment, soil remediation, and chemical recycling of plastic. An entirely novel concept, the "plastic gene", is also proposed to elaborate on some contradictory results. Plastic flotation with clear surface reactions may promote plastic recycling and thereby control waste plastic at the source, save energy, and reduce microplastics. We also predict challenges for clean, efficient, and practical surface modifications and plastic flotation.
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Affiliation(s)
- Hongru Jiang
- College of Chemistry and Chemical Engineering, Central South University, Changsha, 410083 Hunan P.R. China
| | - Yingshuang Zhang
- College of Chemistry and Chemical Engineering, Central South University, Changsha, 410083 Hunan P.R. China
| | - Hui Wang
- College of Chemistry and Chemical Engineering, Central South University, Changsha, 410083 Hunan P.R. China
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