Desalination and Water Treatment
·
2015
·
IF 1.173
Yumei Zhang,Lan Yang,Dongtian Wang,Tao Zhang
For resource utilization, water treatment residual sludge (WTRS) and its cerium-modified product (Ce-WTRS) were used as adsorbents to remove F− from aqueous solution. The adsorbent materials were characterized by energy dispersive X-ray, scanning electron microscope, X-ray diffraction, Fourier transform infrared, and specific surface area test techniques. Different experimental conditions such as pH, initial F− concentration, contract time, and temperature were investigated. The appropriate adsorption capacity was achieved in the pH range of 3–9. Adsorption kinetics, isotherm, and thermodynamic studies were used to illustrate the nature of F− onto adsorbents materials. Good fitting of pseudo-second-order kinetics model indicated the chemisorption nature. Further analyses of intra-particle diffusion model were carried out to determine the rate controlling step. It was found that the Langmuir and Temkin isotherm models fitted the experimental data better. The maximum adsorption capacity (qm) determined by Langmuir isotherm model was 15.45 mg/g for Ce-WTRS, 22% higher than WTRS. The negative values of ΔGθ indicated the feasibility and spontaneity of material-fluoride interaction. ΔHθ >0 for Ce-WTRS demonstrated the endothermic nature, while ΔHθ <0 for WTRS suggested an exothermic procedure. Ion exchange and complex reaction were identified as the main mechanism of fluoride adsorption.
研究领域:
环境科学
·
化学工程
✓ 已验证
DOI
高影响因子
SCIENCE OF THE TOTAL ENVIRONMENT
·
2023
·
IF 9.8
Aixia Chen,Luxue Lv,Ruirui Hu,Xiao Wei,Juanjuan Guan,Xin Meng
Breaking the technical bottleneck of traditional powdered adsorbent in phosphate adsorption application treatment, a macroscopic high adsorption performance aluminum sludge-based composite hydrogel material was constructed to synergistically solve the problems of water eutrophication and aluminum sludge resourcization. In this study, porous Ce-modified aluminum sludge hydrogel microspheres (Ce-AlS-SA) were prepared to improve the surface chemical structure and microscopic morphology of the macroscopic adsorbent material to enhance the adsorption capacity and achieve effective solid-liquid separation. The best adsorption performance of the material (Ce-AlS 12 -SA 1 ) was obtained when the Ce-AlS: SA : Na 2 CO 3 was 12:1:1, and obtained the optimal adsorption conditions by Response Surface Method (RSM) with 1.5 mg/L of the dosage, 4 of pH and 50 mg/L of C phosphate . The maximum adsorption of 20.36 mg P/g was obtained by the Langmuir model at 303 K, which was 2.92 times more than raw sludge. According to the Freundlich and pseudo-second-order kinetic model, the adsorption process is chemisorption ; the multi-stage adsorption process is reflected in the intraparticle diffusion and film diffusion models. The main mechanisms combined with the characterization analysis are electrostatic gravity, ligand exchange , and inner-sphere complexation. Meanwhile, Ce-AlS 12 -SA 1 shows good resistance to interference in the coexistence of multiple ions. Therefore, this material can be recognized as a new material with in-depth, diversified and practical needs for resourceful utilization, which is expected to achieve extensive engineering applications in the future.
研究领域:
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
PROCESS SAFETY AND ENVIRONMENTAL PROTECTION
·
2024
·
IF 6.9
Fangjun Wang,Shiyi Chen,Shubo Chen,Pengxing Yuan,Lunbo Duan,Wenguo Xiang
As the interest in environmentally-friendly energy processes increases, many studies have been focused on producing hydrogen as an alternative energy carrier via catalytic reaction processes. Sorption enhanced water gas shift (SEWGS) that combines WGS and in situ CO 2 removal is a promising technology for high-purity H 2 production and CO 2 capture. In this study, Fe/Ce-modified CaO-Ca 12 Al 14 O 33 bi-functional porous nanotubes were synthesized in one step by template method and applied for H 2 production from SEWGS process. The unique porous nanotube structure fully exposes the catalytic active sites and facilitates the gas-solid transport, resulting in the excellent H 2 production and CO 2 capture performance in SEWGS/regeneration cycles. The introduction of Ce enhances the basicity of the nanotube material, thereby increasing the affinity for CO 2 . The interaction of Fe-Ce improves the redox capability of Fe 2+ and Fe 3+ , which is beneficial to the conversion of CO. In addition, the formed Ca 2 Fe 2 O 5 and Ca 2 CeO 4 both increase the concentration of oxygen vacancies , further enhancing the SEWGS reactivity of the material. The optimal molar ratio of Fe/Ce/Al/Ca is 10/3/10/100, and the CO conversion, H 2 concentration, CO 2 capture capacity of the Fe/Ce-modified bi-functional material were 76.9 %, 70.1 % and 83.2 % after 20 cycles. The effect of Fe/Ce doping on CaO-based materials was investigated at the molecular level using density functional theory (DFT). The results demonstrate that the addition of Ce can effectively maintain the stable structure of Fe-CaO-based materials. The modification of Fe/Ce is expected to promote efficient H 2 generation from CaO-based materials through the SEWGS process.
研究领域:
能源科学
·
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THE ENERGY INSTITUTE
·
2024
·
IF 5.6
Shunnian Xu,Zhiguo Sun,Kaijun Hou,Gang Wang,Meijia Liu,Yahong Zhang,Chenwei Zhang,Zhongdong Zhang
Undesirable side reactions often occur during the catalytic pyrolysis of olefins in FCC gasoline to produce light olefins. We proposed a method to maximize light olefin selectivity by suppressing these side reactions. In this study, P-ZSM-5 and Ce–P-ZSM-5 were prepared by the pore volume impregnation method to investigate the regulatory relationship between their acidity/alkalinity and catalytic pyrolysis. The study found that acid sites could promote the olefin conversion and adjust the cracking pathway. Furthermore, the densities of strong B acid sites and base sites could regulate olefin adsorption, affecting hydrogen transfer activity. Acid strength was crucial in controlling the aromatization reaction. It showed that thermal cracking played a minor role in catalytic pyrolysis, with methane generation mainly resulting from acid sites promoting the cracking of terminal C–C bonds. Loading phosphorus strengthens the acidity of ZSM-5, while loading cerium weakens its acidity and enhances its alkalinity. By optimizing the acidity and alkalinity of ZSM-5, side reactions were suppressed, maximizing the selectivity of light olefins. The results showed that the light olefin selectivity of Ce–P-ZSM-5 increased from 33.2% to over 80%, while the side reaction selectivity decreased from over 60% to below 10%. This work will lay a good foundation for developing catalysts for catalytic pyrolysis of olefins to produce light olefins.
研究领域:
化学工程
·
催化材料科学
✓ 已验证
产品关联
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2022
·
IF 9.136
Xiaohua Cao,Tianhao Ai,Zhizhi Xu,Jichang Lu,Dingkai Chen,Dedong He,Jiangping Liu,Rui Tian,Yutong Zhao,Yongming Luo
High sulfur resistance and high stability of catalysts are crucial for the catalytic decomposition of sulfur-containing volatile organic compounds. In this work, compared to 5Ce-MCM-41, the 5Cr-MCM-41 catalyst exhibited ultra-stability (no activity loss at 600 h) and higher sulfur resistance. The physical structure and chemical characteristics of the catalysts were analyzed by XRD , H 2 -TPR, NH 3 -TPD, CO 2 -TPD, XPS , and TEM. Combining the characterization results, we found that the 5Cr-MCM-41 catalyst presented outstanding catalytic performance due to superior reducibility and appropriate acidity, which results in the conversion of most of the C and S elements in the CH 3 SH to the gas-phase coke- and sulfur-containing products rather than accumulating on the catalyst surface. Meanwhile, the catalytic performance, reaction path, and deactivation mechanism of rare earth metal (Ce) and transition metal (Cr) modified MCM-41 catalysts were systematically investigated by in situ DRIFTS and DFT calculations. Additionally, a new active phase (sulfide state Cr 2 S 3 ) was proposed and proved via accurately designed experiments, which plays a significant role in the collaborative removal of CH 3 SH with hexavalent chromium (Cr(VI)). These findings are beneficial for designing high sulfur resistance catalysts for the removal of CH 3 SH and other sulfur-containing products.
研究领域:
催化化学
·
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
CARBOHYDRATE POLYMERS
·
2024
·
IF 10.7
Ruirui Yang,Fuqing Bai,Liping Mei,Wei Guo,Huanhuan Qiao,Guijie Chen,Junsheng Liu,Fei Ke,Chuanyi Peng,Ruyan Hou,Xiaochun Wan,Huimei Cai
A new zirconium and cerium-modified polyvinyl alcohol (PVA) sodium carboxymethyl cellulose (NaCMC) film (PVA/CMC-Zr-Ce) was synthesized thru a high-speed shear-assisted method and its adsorption for the removal of fluoride was studied, in which the NaCMC provided –COONa for ion exchange between Na and Zr-Ce, thus the loading amount of Zr-Ce on films was accordingly increased. The morphology and structure of PVA/CMC-Zr-Ce were characterized using scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD). Besides, the mechanical properties, water contact angle, and swelling ratio of film were also evaluated. The addition of high-speed shear improved the dispersion of the emulsion system, and PVA/CMC-Zr-Ce film with good adsorption performance and film stability was prepared. While, it was found that the adsorption capacity could reach 67.25 mg/g and equilibrium time could reach 20 min. The adsorption mechanism of PVA/CMC-Zr-Ce revealed that ion exchange between hydroxide and fluoride, electrostatic interactions and complexation were the dominating influencing factors. Based on these findings, it can be concluded that PVA/CMC-Zr-Ce film- synthesized with high-speed shear assistance technique is a promising adsorbent for fluoride removal from water.
研究领域:
材料科学
·
环境科学
·
吸附技术
✓ 已验证
产品关联
DOI
PubMed
高影响因子
APPLIED SURFACE SCIENCE
·
2023
·
IF 6.7
Shuran Liu,Taojin Wang,Xiaodong Wu,Yue Ma,Rui Ran,Duan Weng,Shuang Liu
In this work, silica-alumina mixed oxides with different SiO 2 contents (5% and 30%) were adopted as acidic supports for platinum catalysts for soot oxidation. The obtained catalysts were thermally aged in air at 550, 650 and 750 °C for 2 h, respectively. The catalysts were characterized by transmission electron microscopy (TEM), CO chemisorption, inductively coupled plasma (ICP), N 2 adsorption/desorption, NH 3 temperature-programmed desorption (TPD), H 2 temperature-programmed reduction (TPR), infrared (IR) spectroscopy of CO and NH 3 adsorption, and NO temperature-programmed oxidation (TPO). The acidic support Pt catalysts had higher catalytic activities for NO oxidation and soot oxidation. After aging at 750 ℃, severer sintering of Pt occurred on the acidic supports, and some Pt particles larger than 50 nm formed, resulting in serious deactivation. It was ascribed to metallic state of Pt on the acidic supports with weakened metal-support interactions (SMI). Thus, CeO 2 was added to the silica-alumina support by ball milling to strengthen the SMI via forming Pt-O-Ce bonds. In this way, Pt nanoparticles were anchored to the modified support to inhibit sintering at high temperatures, and the obtained Pt/CeO 2 /SiO 2 -Al 2 O 3 catalyst exhibited both high soot oxidation activity and superior thermal stability.
研究领域:
催化化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2022
·
IF 4.326
Li-Yun Zhang,Jing-Pei Cao,Xue-Yu Ren,Xiao-Bo Feng,Jing-Xian Wang,Zi-Meng He,Tian-Long Liu,Zhen Yang,Xiao-Yan Zhao,Hong-Cun Bai
CeO2 receives extensive researches as an active component due to its providential catalytic center and favorable reducibility. Herein, a series of Ce-modified hierarchical ZSM-5 zeolites (FZ5) were prepared by HF (0.5 mol/L) etching followed by impregnation with different Ce loadings. The role of incorporating extra-framework Ce elements was assessed by catalytic upgrading of the cellulose pyrolysis volatiles to produce light aromatics (LAs). Introducing CeO2 could effectively regulate the acid properties of catalysts with an increase in Lewis acid sites and a decrease in Brönsted acid sites, which could significantly improve the catalytic performance. As a result, the selectivity toward LAs were significantly enhanced and the coke content dramatically decreased. The highest selectivity to LAs and the lowest coke content obtained over 1.0Ce-FZ5 zeolite (loading 1.0 wt % Ce) were 84.0% and 2.42 wt %, respectively. Additionally, the 1.0Ce-FZ5 catalyst exhibited excellent stability, maintaining nearly 90% carbon yield of LAs after the seventh regeneration test. CeO2 modification opened a simple and feasible way for promoting the LAs selectivity and catalyst stability during the reforming of biomass volatiles.
研究领域:
催化化学
·
生物质能源
·
材料化学
·
环境科学
·
能源化工
✓ 已验证
DOI
高影响因子
CHINESE JOURNAL OF CHEMICAL ENGINEERING
·
2022
·
IF 3.898
Suhang Jiang,Lijuan Tan,Yujia Tong,Lijian Shi,Weixing Li
Hydrogen peroxide synthesis by electro-reduction of O 2 to substitute the current anthraquinone process has attracted a great deal of attention. Low oxygen utilization rate and low hydrogen peroxide production remain obstacles to electro-Fenton application. In situ H 2 O 2 generated by electrochemical reaction depends on the electrochemical performance of the cathode and the structure of the reactor. Here, novel graphite felt (GF) modified by La-doped CeO 2 (La–CeO 2 ) was developed as a cathode. A new double chamber electro-Fenton reactor was proposed, where an organic ultrafiltration membrane was used to prevent H 2 O 2 from spreading to the anode. The effects of hydrothermal temperature, time and urea concentration on the electrochemical properties of graphite felt were investigated. The accumulated concentration of H 2 O 2 on the modified cathode reached 218.4 mg·L –1 in 1 h when the optimal conditions of hydrothermal temperature 120 °C and urea concentration 0.55% (mass) in 24 h. The degradation rate of methyl orange reached 98.29%. The new electro-Fenton reactor can efficiently produce hydrogen peroxide to degrade various organic substances and has a high potential for treating wastewater in the chemical industry.
研究领域:
环境工程
·
化学工程
·
废水处理
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THE ENERGY INSTITUTE
·
2023
·
IF 5.7
Tianli Sun,Ye Wu,Jian Mei,Hang Zhu,Kun Qian,Dong Liu
Using oxygen carrier to relieve uneven mixing of fuel and air under harsh conditions (high temperature and short residence time) is a promising strategy to improve fuel efficiency. In this paper, a range of cerium modified ferric oxide oxygen carriers with excellent redox capability and stability was fabricated to investigate the ethylene rapid oxidation performance and the gas–solid surface reaction of ethylene and iron oxide was studied with density functional theory. The experimental results show that the oxygen carrier with the mole ratio of ferrum : cerium is 9:1 performed the best ethylene oxidation characteristic, because the addition of cerium improved oxygen vacancy capacity to enhance the oxidation for ethylene and its pyrolysis products, which was also confirmed with density functional theory study. Due to the role of both, the ethylene and its pyrolysis products were converted into carbon dioxide and water quickly and effectively (carbon dioxide yield >92%).
研究领域:
化学工程
·
材料科学
·
能源技术
·
催化
✓ 已验证
产品关联
DOI
高影响因子
Nature Communications
·
2024
·Vol. 15
·期 1
·1-12
·
IF 14.7
Sun Mengyao,Chen Yanjun,Fan Xiaoqiang,Li Dong,Song Jiaxin,Yu Ke,Zhao Zhen
Photocatalytic oxidative coupling of methane with oxygen is promising to obtain valuable muti-carbon products, yet suffering low reactivity. Here, we apply cerium modifications on zinc oxide-supported gold catalysts based on the electronic asymmetry design of lattice oxygen to improve the coupling activity. The methane conversion rate exceeds 16000 μmol g −1 h −1 with muti-carbon selectivity of 94.9% and catalytic durability of 3 days, and it can increase to 34000 μmol g −1 h −1 under more thermal assistance, with a turnover frequency of 507 h −1 for ethane and an apparent quantum efficiency of 33.7% at 350 nm. According to systematic characterizations and theoretical analysis, cerium dopants not only can boost the formation of reactive oxygen species but also intervene in the vivacity of lattice oxygen by manipulating metal-oxygen bond strength, thereby leading to favorable methyl desorption to form ethane and quick water release. This work provides insight into the rational design of efficient photocatalysts for aerobic methane-to-ethane conversion.
研究领域:
催化
·
材料科学
·
化学工程
·
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）