1
|
Sharma H, Kaith BS, Kumar R, Mehra R, Bhatti MS. Fabrication of cellulose-collagen based biosorbent as eco-friendly scavengers for uranyl ions. Int J Biol Macromol 2024; 266:131400. [PMID: 38582480 DOI: 10.1016/j.ijbiomac.2024.131400] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2023] [Revised: 03/07/2024] [Accepted: 04/03/2024] [Indexed: 04/08/2024]
Abstract
The aim of the present research is to fabricate a biosorbent using agricultural waste for removal of uranium from contaminated water i.e. "waste to wealth" approach. Cellulose extracted from wheat straw was mercerized and a novel semi-interpenetrating polymer network (semi-IPN) was fabricated through graft copolymerization of polyvinyl alcohol onto hybrid mercerized cellulose + collagen backbone. Response surface methodology was used for optimization of different reaction parameters as a function of % grafting (195.1 %) was carried out. Semi-IPN was found to possess higher thermal stability. Adsorption results revealed that the optimum parameters for the elimination of uranium using semi-IPN were: adsorbent dose = 0.15 g, pH = 6.0, contact time = 120 min and initial U (VI) concentration = 100 μg/L. The pseudo-second-order kinetic model gave the best description of the adsorption equilibrium data as the calculated qe value is nearest to the experimental qe for the different initial U(VI) concentrations. Adsorption experiments followed Langmuir isotherm with R2 = 0.999. Furthermore, recyclability and reusability studies showed that the adsorption efficiency of semi-IPN was 82 % after 5 cycles indicating the superior recycling execution of fabricated biosorbent. Thus, the fabricated ecofriendly device can be used effectively for the removal of uranium from contaminated wastewater sources.
Collapse
Affiliation(s)
- Himani Sharma
- Smart Materials Laboratory, Department of Chemistry, Dr B R Ambedkar National Institute of Technology, Jalandhar, Punjab 144 008, India.
| | - Balbir Singh Kaith
- Smart Materials Laboratory, Department of Chemistry, Dr B R Ambedkar National Institute of Technology, Jalandhar, Punjab 144 008, India.
| | - Rakesh Kumar
- Smart Materials Laboratory, Department of Chemistry, Dr B R Ambedkar National Institute of Technology, Jalandhar, Punjab 144 008, India
| | - Rohit Mehra
- Department of Physics, Dr B R Ambedkar National Institute of Technology, Jalandhar, Punjab 144 008, India
| | - Manpreet Singh Bhatti
- Department of Botanical and Environmental Sciences, Guru Nanak Dev University, Amritsar, Punjab 143 005, India
| |
Collapse
|
2
|
Sun F, Wang D, Hu Q, Jiao R, Zhang J, Li N, Li J. Hydrolyzed Hydrated Titanium Oxide on Laser-Induced Graphene as CDI Electrodes for U(VI) Adsorption. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2024; 40:704-713. [PMID: 38109847 DOI: 10.1021/acs.langmuir.3c02927] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2023]
Abstract
Recently, laser-induced graphene (LIG), which has been successfully applied in CDI technology (directly without a complex preparation process), has gained considerable attention. However, the raw LIG electrode with a limited number of active sites exhibits low adsorption efficiency. Therefore, the search for a suitable and effective method to modify LIG to improve its electroadsorption performance is significant. Herein, a very simple titration hydrolysis method is adopted to modify LIG, resulting in a layer of hydrated titanium oxide (HTO) being synthesized on the surface of LIG. The LIG/HTO composites possess a good adsorption property since covering the surface of LIG with a layer of HTO can greatly improve the adsorption capacity of LIG. Moreover, with the addition of HTO, not only the proton transfer ability of LIG has been enhanced but also considerable specific capacitance has been enlarged. As a result, LIG/HTO composite as CDI electrode displays a maximum theoretical adsorption capacity of 1780.89 mg/g at 1.2 V, and the capacitance of LIG/HTO composite material is 4.74 times higher than LIG. During the electroadsorption process, Ti4+ is reduced to Ti3+ under external voltage, and O2- is produced through oxidation. Meanwhile, part of the U (VI) is hydrolyzed into UO3·2H2O under the action of -OH, and some combine with O2- to produce UO4·4H2O.
Collapse
Affiliation(s)
- Fuwei Sun
- University of Science and Technology of China, Hefei 230026, PR China
- Institute of Plasma Physics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, China
| | - De Wang
- University of Science and Technology of China, Hefei 230026, PR China
- Institute of Plasma Physics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, China
| | - Qinyan Hu
- University of Science and Technology of China, Hefei 230026, PR China
- Institute of Plasma Physics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, China
| | - Ranran Jiao
- University of Science and Technology of China, Hefei 230026, PR China
- Institute of Plasma Physics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, China
| | - Jianfeng Zhang
- University of Science and Technology of China, Hefei 230026, PR China
- Institute of Plasma Physics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, China
| | - Nian Li
- Institute of Solid State Physics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, Anhui, China
| | - Jiaxing Li
- University of Science and Technology of China, Hefei 230026, PR China
- Institute of Plasma Physics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, China
| |
Collapse
|
3
|
Zhu W, Li X, Wang D, Fu F, Liang Y. Advanced Photocatalytic Uranium Extraction Strategies: Progress, Challenges, and Prospects. NANOMATERIALS (BASEL, SWITZERLAND) 2023; 13:2005. [PMID: 37446529 DOI: 10.3390/nano13132005] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Revised: 07/03/2023] [Accepted: 07/04/2023] [Indexed: 07/15/2023]
Abstract
Nuclear energy with low carbon emission and high-energy density is considered as one of the most promising future energy sources for human beings. However, the use of nuclear energy will inevitably lead to the discharge of nuclear waste and the consumption of uranium resources. Therefore, the development of simple, efficient, and economical uranium extraction methods is of great significance for the sustainable development of nuclear energy and the restoration of the ecological environment. Photocatalytic U(VI) extraction technology as a simple, highly efficient, and low-cost strategy, received increasing attention from researchers. In this review, the development background of photocatalytic U(VI) extraction and several photocatalytic U(VI) reduction mechanisms are briefly described and the identification methods of uranium species after photocatalytic reduction are addressed. Subsequently, the modification strategies of several catalysts used for U(VI) extraction are summarized and the advantages and disadvantages of photocatalytic U(VI) extraction are compared. Additionally, the research progress of photocatalytic technology for U(VI) extraction in actual uranium-containing wastewater and seawater are evaluated. Finally, the current challenges and the developments of photocatalytic U(VI) extraction technology in the future are prospected.
Collapse
Affiliation(s)
- Wangchuan Zhu
- Research Institute of Comprehensive Energy Industry Technology, School of Chemistry & Chemical Engineering, Yan'an University, Yan'an 716000, China
| | - Xiang Li
- Research Institute of Comprehensive Energy Industry Technology, School of Chemistry & Chemical Engineering, Yan'an University, Yan'an 716000, China
| | - Danjun Wang
- Research Institute of Comprehensive Energy Industry Technology, School of Chemistry & Chemical Engineering, Yan'an University, Yan'an 716000, China
| | - Feng Fu
- Research Institute of Comprehensive Energy Industry Technology, School of Chemistry & Chemical Engineering, Yan'an University, Yan'an 716000, China
| | - Yucang Liang
- Institute of Inorganic Chemistry, University of Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany
| |
Collapse
|
4
|
Zhang Y, Mei B, Shen B, Jia L, Liao J, Zhu W. Preparation of biochar@chitosan-polyethyleneimine for the efficient removal of uranium from water environment. Carbohydr Polym 2023; 312:120834. [PMID: 37059560 DOI: 10.1016/j.carbpol.2023.120834] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2022] [Revised: 03/07/2023] [Accepted: 03/17/2023] [Indexed: 03/28/2023]
Abstract
A novel chitosan-based composite with rich active sites was synthesized by uniformly dispersing biochar into the cross-linked network structure formed by chitosan and polyethyleneimine. Due to the synergistic effect of biochar (minerals) and chitosan-polyethyleneimine interpenetrating network (amino and hydroxyl), the chitosan-based composite possessed an excellent adsorption performance for uranium(VI). It could rapidly (<60 min) achieve a high adsorption efficiency (96.7 %) for uranium(VI) from water and a high static saturated adsorption capacity (633.4 mg/g), which was far superior to other chitosan-based adsorbents. Moreover, the separation for uranium(VI) on the chitosan-based composite was suitable for a variety of actual water environments and the adsorption efficiencies all exceeded 70 % in different water bodies. The soluble uranium(VI) could be completely removed by the chitosan-based composite in the continuous adsorption process, which could meet the permissible limits of the World Health Organization. In sum, the novel chitosan-based composite could overcome the bottleneck of current chitosan-based adsorption materials and become a potential adsorbent for the remediation of actual uranium(VI) contaminated wastewater.
Collapse
Affiliation(s)
- Yong Zhang
- State Key Laboratory of Environment-friendly Energy Materials, Sichuan Co-Innovation Center for New Energetic Materials, National Co-innovation Center for Nuclear Waste Disposal and Environmental Safety, Nuclear Waste and Environmental Safety Key Laboratory of Defense, School of National Defence Science & Technology, Southwest University of Science and Technology, Mianyang 621010, China
| | - Bingyu Mei
- State Key Laboratory of Environment-friendly Energy Materials, Sichuan Co-Innovation Center for New Energetic Materials, National Co-innovation Center for Nuclear Waste Disposal and Environmental Safety, Nuclear Waste and Environmental Safety Key Laboratory of Defense, School of National Defence Science & Technology, Southwest University of Science and Technology, Mianyang 621010, China
| | - Binhao Shen
- State Key Laboratory of Environment-friendly Energy Materials, Sichuan Co-Innovation Center for New Energetic Materials, National Co-innovation Center for Nuclear Waste Disposal and Environmental Safety, Nuclear Waste and Environmental Safety Key Laboratory of Defense, School of National Defence Science & Technology, Southwest University of Science and Technology, Mianyang 621010, China
| | - Lingyi Jia
- State Key Laboratory of Environment-friendly Energy Materials, Sichuan Co-Innovation Center for New Energetic Materials, National Co-innovation Center for Nuclear Waste Disposal and Environmental Safety, Nuclear Waste and Environmental Safety Key Laboratory of Defense, School of National Defence Science & Technology, Southwest University of Science and Technology, Mianyang 621010, China
| | - Jun Liao
- State Key Laboratory of Environment-friendly Energy Materials, Sichuan Co-Innovation Center for New Energetic Materials, National Co-innovation Center for Nuclear Waste Disposal and Environmental Safety, Nuclear Waste and Environmental Safety Key Laboratory of Defense, School of National Defence Science & Technology, Southwest University of Science and Technology, Mianyang 621010, China..
| | - Wenkun Zhu
- State Key Laboratory of Environment-friendly Energy Materials, Sichuan Co-Innovation Center for New Energetic Materials, National Co-innovation Center for Nuclear Waste Disposal and Environmental Safety, Nuclear Waste and Environmental Safety Key Laboratory of Defense, School of National Defence Science & Technology, Southwest University of Science and Technology, Mianyang 621010, China..
| |
Collapse
|
5
|
Zhou L, Dong F, Xi X, Zhou L, Dai Q, Liu M, Han Y, Yang G, Zhang Y. Arsenic triggered nano-sized uranyl arsenate precipitation on the surface of Kocuria rosea. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2023; 262:107168. [PMID: 37003252 DOI: 10.1016/j.jenvrad.2023.107168] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Revised: 03/15/2023] [Accepted: 03/27/2023] [Indexed: 06/19/2023]
Abstract
Arsenic (As) and uranium (U) frequently occur together naturally and, in consequence, transform into cocontaminants at sites of uranium mining and processing, yet the simultaneous interaction process of arsenic and uranium has not been well documented. In the present contribution, the influence of arsenate on the removal and reduction of uranyl by the indigenous microorganism Kocuria rosea was characterized using batch experiments combined with species distribution calculation, SEM-EDS, FTIR, XRD and XPS. The results showed that the coexistence of arsenic plays an active role in Kocuria rosea growth and the removal of uranium under neutral and slightly acidic conditions. U-As complex species of UO2HAsO4 (aq) had a positive effect on uranium removal, while Kocuria rosea cells appeared to have a large specific surface area serving as attachment sites. Furthermore, a large number of nano-sized flaky precipitates, constituted by uranium and arsenic, attached to the surface of Kocuria rosea cells at pH 5 through P=O, COO-, and C=O groups in phospholipids, polysaccharides, and proteins. The biological reduction of U(VI) and As(V) took place in a successive way, and the formation of a chadwickite-like uranyl arsenate precipitate further inhibited U(VI) reduction. The results will help to design more effective bioremediation strategies for arsenic-uranium cocontamination.
Collapse
Affiliation(s)
- Lei Zhou
- Fundamental Science on Nuclear Wastes and Environmental Safety Laboratory, Southwest University of Science and Technology, Mianyang, Sichuan, 621010, China; School of Life Science and Engineering, Southwest University of Science and Technology, Mianyang, Sichuan, 621010, China
| | - Faqin Dong
- School of Environment and Resource, Southwest University of Science and Technology, Mianyang, Sichuan, 621010, China; Key Laboratory of Solid Waste Treatment and the Resource Recycle, Southwest University of Science and Technology, Mianyang, Sichuan, 621010, China.
| | - Xiangyu Xi
- School of Life Science and Engineering, Southwest University of Science and Technology, Mianyang, Sichuan, 621010, China
| | - Lin Zhou
- School of Environment and Resource, Southwest University of Science and Technology, Mianyang, Sichuan, 621010, China; Key Laboratory of Solid Waste Treatment and the Resource Recycle, Southwest University of Science and Technology, Mianyang, Sichuan, 621010, China
| | - Qunwei Dai
- Fundamental Science on Nuclear Wastes and Environmental Safety Laboratory, Southwest University of Science and Technology, Mianyang, Sichuan, 621010, China
| | - Mingxue Liu
- School of Life Science and Engineering, Southwest University of Science and Technology, Mianyang, Sichuan, 621010, China
| | - Ying Han
- School of Life Science and Engineering, Southwest University of Science and Technology, Mianyang, Sichuan, 621010, China
| | - Gang Yang
- School of Life Science and Engineering, Southwest University of Science and Technology, Mianyang, Sichuan, 621010, China
| | - Yongde Zhang
- Fundamental Science on Nuclear Wastes and Environmental Safety Laboratory, Southwest University of Science and Technology, Mianyang, Sichuan, 621010, China
| |
Collapse
|
6
|
Design and synthesis of a novel bifunctional polymer with malonamide and carboxyl group for highly selective separation of uranium (VI). Sep Purif Technol 2022. [DOI: 10.1016/j.seppur.2022.122115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
|
7
|
Bao Y, Liu Y, Wang C, Wang Y, Yuan D, Xu J, Zhu Z, He Y, Liu J. Synergistic removal of U(VI) from aqueous solution by TAC material: Adsorption behavior and mechanism. Appl Radiat Isot 2022; 190:110512. [DOI: 10.1016/j.apradiso.2022.110512] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Revised: 09/17/2022] [Accepted: 10/11/2022] [Indexed: 11/02/2022]
|
8
|
Qiu Y, Ren LF, Xia L, Zhong C, Shao J, Zhao Y, Van der Bruggen B. Recovery of Fluoride-Rich and Silica-Rich Wastewaters as Valuable Resources: A Resource Capture Ultrafiltration-Bipolar Membrane Electrodialysis-Based Closed-Loop Process. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:16221-16229. [PMID: 36287592 DOI: 10.1021/acs.est.2c04704] [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] [Indexed: 06/16/2023]
Abstract
Traditional technologies such as precipitation and coagulation have been adopted for fluoride-rich and silica-rich wastewater treatment, respectively, but waste solid generation and low wastewater processing efficiency are still the looming concern. Efficient resource recovery technologies for different wastewater treatments are scarce for environment and industry sustainability. Herein, a resource capture ultrafiltration-bipolar membrane electrodialysis (RCUF-BMED) system was designed into a closed-loop process for simultaneous capture and recovery of fluoride and silica as sodium silicofluoride (Na2SiF6) from mixed fluoride-rich and silica-rich wastewaters, as well as achieving zero liquid discharge. This RCUF-BMED system comprised two key parts: (1) capture of fluoride and silica from two wastewaters using acid, and recovery of the Na2SiF6 using base by UF and (2) UF permeate conversion for acid/base and freshwater generation by BMED. With the optimized RCUF-BMED system, fluoride and silica can be selectively captured from wastewater with removal efficiencies higher than 99%. The Na2SiF6 recovery was around 72% with a high purity of 99.1%. The aging and cyclic experiments demonstrated the high stability and recyclability of the RCUF-BMED system. This RCUF-BMED system has successfully achieved the conversion of toxic fluoride and silica into valuable Na2SiF6 from mixed wastewaters, which shows great application potential in the industry-resource-environment nexus.
Collapse
Affiliation(s)
- Yangbo Qiu
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, No. 800 Dongchuan Road, Shanghai200240, P. R. China
| | - Long-Fei Ren
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, No. 800 Dongchuan Road, Shanghai200240, P. R. China
- Chongqing Research Institute of Shanghai Jiao Tong University, No. 168 Liangjiang Road, Chongqing401120, P. R. China
| | - Lei Xia
- Division of Soil and Water Management, KU Leuven, Kasteelpark Arenberg 20, 3001Leuven, Belgium
| | - Changmei Zhong
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, No. 800 Dongchuan Road, Shanghai200240, P. R. China
| | - Jiahui Shao
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, No. 800 Dongchuan Road, Shanghai200240, P. R. China
| | - Yan Zhao
- Department of Chemical Engineering, KU Leuven, Celestijnenlaan 200F, B-3001Leuven, Belgium
| | - Bart Van der Bruggen
- Department of Chemical Engineering, KU Leuven, Celestijnenlaan 200F, B-3001Leuven, Belgium
| |
Collapse
|
9
|
Cao KF, Chen Z, Wu YH, Mao Y, Shi Q, Chen XW, Bai Y, Li K, Hu HY. The noteworthy chloride ions in reclaimed water: Harmful effects, concentration levels and control strategies. WATER RESEARCH 2022; 215:118271. [PMID: 35298995 DOI: 10.1016/j.watres.2022.118271] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Revised: 01/27/2022] [Accepted: 03/06/2022] [Indexed: 06/14/2023]
Abstract
Chloride ions (Cl-), which are omnipresent in reclaimed water, can cause various problems in water reuse systems, especially during water transmission and at end use sites. Although reverse osmosis (RO) is considered as an effective technology to reduce chloride, its high investment and complex maintenance requirements hinder its application in many water reclamation plants (WRPs). Recently, several technologies bringing new options to better deal with chloride have gained increased attention. This review provides detailed information on the harmful effects, concentration levels, and sources of chloride in reclaimed water and summarizes and discusses various chloride removal technologies, including non-selective methods (e.g., membrane filtration, adsorption and ion exchange, oxidation, and electrochemical methods) and selective methods (e.g. precipitation and specially designed electrochemical methods). Among these, Friedel's salt precipitation and capacitive deionization showed attractive development potential. This review also proposes a holistic framework for chloride control from aspects of "Fit-for-Purpose" planning, technical system development, and whole process optimization, which could facilitate the planning and operation of long-term sustainable water reuse practices.
Collapse
Affiliation(s)
- Ke-Fan Cao
- 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
| | - Zhuo Chen
- 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, PR China.
| | - Yin-Hu Wu
- 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, PR China
| | - Yu Mao
- 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
| | - Qi Shi
- 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
| | - Xiao-Wen Chen
- 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
| | - Yu Bai
- Beijing Laboratory for Environmental Frontier Technologies, Beijing 100084, PR China; Research and Development Center, Beijing Drainage Group Co., Ltd, Beijing 100124, PR China
| | - Kuixiao Li
- Beijing Laboratory for Environmental Frontier Technologies, Beijing 100084, PR China; Research and Development Center, Beijing Drainage Group Co., Ltd, Beijing 100124, 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; Beijing Laboratory for Environmental Frontier Technologies, Beijing 100084, PR China; Research Institute for Environmental Innovation (Suzhou), Tsinghua, Jiangsu, Suzhou, 215163, PR China
| |
Collapse
|