SCIENCE OF THE TOTAL ENVIRONMENT
·
2021
·
IF 7.963
Peigang He,Qikun Wang,Shuai Fu,Meiling Wang,Shengjian Zhao,Xuzhao Liu,Yuqi Jiang,Dechang Jia,Yu Zhou
This paper reports a facile route to prepare bulk zeolites with tunable phase compositions and microstructures by combining hydrothermal treatment and geopolymer precursor technique. Amorphous Na-based geopolymer (NaGP) is transformed into crystalline analcime following hydrothermal treatments. By systematically investigating the effects of hydrothermal conditions on the phase compositions and microstructures of the products, the optimal hydrothermal procedure is screened as treating NaGP in 1 M NaOH solution at 160 °C for 6 h. Furthermore, we achieve control over phase compositions of the resulting bulk zeolites by tailoring the initial Na/K ratio of geopolymer precursors. For instance, treating the geopolymer precursor with a Na/K ratio of 9: 1 under the optimal hydrothermal procedure leads to the formation of zeolite consisting of analcime and zeolite-P. The as-prepared adsorbents exhibit outstanding adsorption performance for the hazardous elements, among which analcime-zeolite-P shows an adsorption efficiency of 93.3% for Cs + , and NaGP exhibits an adsorption efficiency of 99.6% for Sr 2+ . Moreover, we reveal the mechanisms underlying the adsorption of Cs + and Sr 2+ in the adsorbents to be chemisorption . Meanwhile, ion exchanges also occur in NaGP and analcime-zeolite-P during Cs + adsorption. These results render geopolymers and their derived bulk zeolites promising for hazardous elements adsorption.
研究领域:
材料科学
·
环境科学
✓ 已验证
DOI
高影响因子
RSC Advances
·
2023
·Vol. 13
·期 10
·6346-6355
·
IF 3.9
Lina Wu,Huiping Wang,Xiangqian Kong,Haibo Wei,Sheng Chen,Lisheng Chi
Effective removal of strontium isotopes in radioactive waste streams has important implications for the environment and the sustainable development of nuclear energy. In this work, a zirconium phosphate/18-crown-ether-6 (ZrP/18C6) composite was prepared using the intercalation method by loading crown ether into zirconium phosphate. The composite was structurally and morphologically characterized by XRD, FT-IR, XPS, and SEM. The adsorption experiments of Sr2+ onto the ZrP/18C6 composite were conducted as a function of temperature, pH, Sr2+ concentration and competing ions. The results indicate ZrP/18C6 can adsorb 98.6% of Sr2+ within 30 minutes at an Sr2+ concentration of 100 mg L−1 and maintain a high removal rate with a distribution coefficient of 7 × 105 mL g−1 when Sr2+ is at a low level of 4.28 mg L−1. The ZrP/18C6 composite reached a maximum adsorption capacity of 195.74 mg g−1 at an Sr2+ concentration of 380 mg L−1, which is significantly higher than the 43.03 mg g−1 of α-ZrP. The adsorption performance of Sr2+ onto ZrP/18C6 is not significantly affected by temperature, pH and competing ions. Furthermore, the adsorption kinetics and thermodynamics were analyzed based on the adsorption data obtained in the present work. It is shown that the adsorption of Sr2+ onto ZrP/18C6 follows the pseudo-second-order model and the Langmuir monolayer model, respectively. Additionally, the adsorption mechanism of Sr2+ by ZrP/18C6 is discussed.
研究领域:
环境科学
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核化学
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材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
SCIENCE OF THE TOTAL ENVIRONMENT
·
2023
·
IF 9.8
Fangfei Cai,Funing Ma,Xiaoying Zhang,Paul Reimus,Linlin Qi,Yu Wang,Di Lu,Hung Vo Thanh,Zhenxue Dai
The disposal of high-level radioactive waste in deep geological repositories is a critical environmental issue . The presence of bentonite colloids generated in the engineering barrier can significantly impact the transport of radionuclides , but their effect on radionuclide sorption in granite remains poorly understood. This study aimed to investigate the sorption characteristics of strontium (Sr) on granite as well as on the coexistence system of granite and colloids under various hydrogeochemical conditions, through batch experiments. Fourier transform infrared spectroscopy was employed to analyze the sorption forms of Sr on granite before and after sorption. Several hydrogeochemical factors were examined, including contact time, pH, ionic strength, coexisting ions, and bentonite and humic acid colloid concentration. Among these factors, the concentration of bentonite colloids exhibited a significant effect on Sr sorption. Within a specific range of colloid concentration, the sorption of Sr on the solid system increased linearly with the bentonite colloid concentration. pH and ionic strength were also found to play crucial roles in the sorption process. At low pH, Sr sorption primarily occurred through the outer sphere's surface complexation and Na + /H + ion exchange. However, at high pH, inner sphere surface complexation dominated the process. As the ionic strength increased, electrostatic repulsion gradually increased, resulting in fewer binding sites for particle aggregation and Sr sorption on bentonite colloids. The results also indicate that with increasing pH, the predominant forms of Sr in the solution transitioned from SrHCO 3 + and SrCl + to SrCO 3 and SrCl + . This was mainly due to the ion exchange of Ca 2+ /Mg 2+ in plagioclase and biotite , forming SrCO 3 precipitation. These findings provide valuable insights into the transport behavior of radionuclides in the subsurface environment of the repository and highlight the importance of considering bentonite colloids and other hydrogeochemical factors when assessing the environmental impact of high-level radioactive waste disposal .
研究领域:
环境科学
·
放射生物学
✓ 已验证
DOI
PubMed
高影响因子
Journal of Materials Chemistry A
·
2014
·Vol. 3
·期 3
·1287-1297
·
IF 0
Yan Liu,Xiangguo Meng,Min Luo,Minjia Meng,Liang Ni,Jian Qiu,Zhaoyong Hu,Fangfang Liu,Guoxing Zhong,Zhanchao Liu,Yongsheng Yan
A novel hydrophilic ion-imprinted polymer based on graphene oxide has been synthesized by reversible addition–fragmentation chain transfer (RAFT) polymerization with surface imprinting technique. Methylacrylic acid is used as a hydrophilic functional monomer. The resultant adsorbent is verified by UV-vis scanning spectrophotometer, Fourier transmission infrared spectrometry, scanning electron microscopy, transmission electron microscopy, atomic force microscopy, X-ray diffraction, water contact angle measurements, and thermogravimetric analysis. The results suggest that the surface imprinted polymer synthesized by RAFT is a homogeneous thin layer. Owing to the intrinsic advantages of controlling/living polymerization and surface imprinting technology, the obtained RAFT surface ion-imprinted polymer (RAFT-IIP) exhibits excellent imprinting efficiency and adsorption capacity in comparison to the ion-imprinted polymer prepared by traditional radical polymerization. Furthermore, the adsorption isotherm and recognizing ability towards Sr(II) onto RAFT-IIP and non-imprinted polymer (NIP) are compared in batch experiments. The equilibrium data are well fitted by Langmuir model and RAFT-IIP has higher selectivity and nearly four times larger Langmuir calculated maximum adsorption capacity (145.77 mg g−1) than that of NIP at 25 °C. Meanwhile, RAFT-IIP is regenerated and found to be suitable for reuse in successive adsorption–desorption cycles five times without significant loss in adsorption capacity.
研究领域:
材料科学
·
环境科学
✓ 已验证
产品关联
DOI
RSC Advances
·
2016
·Vol. 6
·期 86
·83288-83295
·
IF 3.289
Chongmin Liu,Shuai Liu,Pingxiao Wu,Yaping Dai,Lytuong Tran,Nengwu Zhu,Chuling Guo,Ihsanullah Sohoo
Modified calcium saturated montmorillonite (Mt) was prepared at different 3-aminopropyltriethoxysilane (APTES) loadings through grafting. The as-products were characterized by XRD, FTIR and elemental analysis. Surface analysis such as acidity was examined at different H+ concentrations, showing that the release of OH− from the modified samples increased in the following order: APTES4.0CEC–Mt > APTES3.0CEC–Mt > APTES2.0CEC–Mt > APTES1.0CEC–Mt. Batch experiments were conducted and different conditions (pH, temperature and co-existing ions) were used to evaluate the adsorption capacity of the modified samples. The study developed a new way to confirm the mechanism, which indicated that ligand adsorption was the dominant sorption mechanism for Sr(II) uptake onto APTES–Mts. In general, APTES grafted montmorillonite possessed a higher efficiency of Sr(II) uptake and showed great potential for Sr(II)-rich wastewater treatment.
研究领域:
环境科学
·
材料科学
·
化学工程
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环境污染治理
·
吸附科学
✓ 已验证
DOI
高影响因子
ACS Applied Materials & Interfaces
·
2023
·
IF 9.5
Jie Li,Jianhui Lan,Runjian Cao,Jun Sun,Xiangdong Ding,Xue Liu,Liyong Yuan,Weiqun Shi
Covalent organic frameworks (COFs) with crown ether units have drawn great attention due to their potential applications in adsorption, catalysis, and sensing. However, employing crown ethers to construct COFs is still challenging in light of the flexible nature of macrocycles. Here, a highly crystalline one-dimensional covalent organic framework (1D-18C6-COF) with crown ether units on the ribbon edge was synthesized. The water-mediated hydrogen bond network and π–π stacking hold the 1D COF ribbons together. The combination of experimental and DFT studies demonstrated that the hydrogen bond network plays a crucial role in the structure crystallinity. The 1D-18C6-COF was applied as an adsorbent for strontium, and it exhibited rapid kinetics with good selectivity. In the competitive adsorption experiment, a separation factor of 1900 was achieved, representing one of the largest values for cesium/strontium separation. This work provides new insights into the design and functional exploration of crystalline COFs with flexible units.
研究领域:
材料科学
·
化学
·
环境科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）