ENVIRONMENTAL GEOCHEMISTRY AND HEALTH
·
2024
·Vol. 47
·期 1
·1-18
·
IF 3.2
Gong Huichun,Ke Pingchao,Zhou Yipeng,Xu Lingling,He Guang,Jian Peng
Fluoride contamination is a serious environmental problem in lepidolite hydrometallurgy wastewater. The treatment of fluoride-bearing wastewater is challenging because of the presence of coexisting ions including lithium (Li + ), rubidium (Rb + ), silicate (SiO 3 2− ), sulfate radical (SO 4 2− ). However, aluminum-modified zeolite (Al@zeolite) with sufficient hydroxyl groups and high adaptability has unique advantages for eliminating fluoride from lepidolite hydrometallurgy wastewater. Al@zeolite was prepared on natural zeolite by an atmospheric process and then used for the adsorption of fluorine from fluoride-bearing wastewater produced by the lepidolite hydrometallurgy process. The results of material characterization confirmed the successful immobilization of aluminum within the zeolite pores and indicated the formation of zeolite-Al–OH. The zeolite host significantly enhanced the chemical stability of Al@zeolite against pH changes for a wide pH range of 2.0–10.0. The adsorbent had a surface area of 33.46 m 2 /g and demonstrated excellent capacity and selectivity for fluoride adsorption. Notably, a maximum adsorption of 98.6% was observed at a pH value of 6.0 for a duration of 20 min with a fluoride content of 20 mg/L, and the equilibrium concentration decreased to 0.4 mg/L. The results of fluorine adsorption showed that fluoride uptake onto Al@zeolite agreed well with the pseudo-second-order kinetic model and the Langmuir isotherm model. The reusability of the substance was evaluated for up to eight cycles following consecutive regeneration with 0.2 mol/L AlCl 3 . The exhausted Al@zeolite was effectively regenerated through simple alkaline treatment for recycling. The above results verified that Al@zeolite is a new kind of efficient defluoridation adsorbent for lepidolite hydrometallurgy wastewater with practical application prospects.
研究领域:
环境科学
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材料科学
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产品关联
DOI
PubMed
高影响因子
IONICS
·
2024
·
IF 2.4
Yang Xue,Liu Aimin,Zhang Xin,Guan Pingping,Liu Yubao,Huang Haitao,Shi Zhongning
Aluminum chloride and triethylamine hydrochloride were employed in the synthesis of an AlCl 3 -Et 3 NHCl electrolyte. An aluminum sheet was utilized as the anode for the electrodeposition of metallic aluminum onto a copper substrate. This study aimed to investigate the effects of deposition potential on the morphology of the aluminum coating, the deposition mechanism, and the changes in Al(III) complex ions during the electrodeposition process. The results indicated that a deposition potential of − 0.3 V (vs. Al) produced aluminum coatings that were uniformly dense and securely adhered to the substrate. When electrodeposition occurred at − 0.5 V (vs. Al), the substrate surface exhibited aluminum nanowires with an approximate diameter of 367 nm. XRD analysis indicated a more pronounced (200) preferred orientation in the aluminum layer deposited at more negative potentials. Raman spectroscopy analysis detected the presence of AlCl 4 − and Al 2 Cl 7 − anions in the AlCl 3 -Et 3 NHCl system before electrodeposition, followed by the formation of Al 3 Cl 10 − complex ions in the system under potentiostatic control.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Materials Research and Technology-JMR&T
·
2021
·
IF 5.039
Yuxiao Xue,Jian Pan,Deqing Zhu,Zhengqi Guo,Hongyu Tian,Yue Shi,Shenghu Lu
Iron ores always contain several forms of alumina, which may have different effect on sintering performance. In this paper, sinter pot tests were systematically conducted with various alumina types and contents by means of alumina additives substituting for the corresponding types of alumina, and the relevant action mechanism on sintering performance was clarified by the mineralogy of product sinter. The results show that kaolinite is beneficial to the granulation process rather than other three alumina types. In addition, it contributes to relatively better sintering performance while aluminous goethite ranks the only next, followed by gibbsite and free alumina. Mechanism analysis indicates that kaolinite and aluminous goethite are preferable to achieve relatively lower sinter porosity and higher amount of silico-ferrite of calcium and alumina (SFCA) compared with gibbsite and free alumina. Besides, the former two alumina types are apt to promote the formation of higher strength SFCA such as dendritic and acicular SFCA. Furthermore, much tighter interlocking texture in product sinter is formed as alumina occurs in kaolinite or aluminous goethite. Kaolinite and aluminous goethite are the preferably desirable alumina types for sintering rather than free alumina and gibbsite.
研究领域:
冶金工程
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材料科学
✓ 已验证
DOI
高影响因子
International Journal of Applied Ceramic Technology
·
2018
·Vol. 15
·期 6
·1490-1501
·
IF 1.165
Xiangli Kong,Minghui Qiu,Anran Wang,Lu Yang,Rongfei Zhou,Yiqun Fan,Deshuang Kong,Changjun Gu
The adhesion and cohesion between the coating layers and the ceramic honeycombs are usually one of the key issues in the preparation of high-performance zeolite-based/Monolith catalysts. In this work, we investigate the deposition of high-efficiency Cu-SAPO-34 catalyst on a cordierite monolith with special focus on the impact of alumina binders on the structure, mechanical adhesion and cohesion, and catalytic performance of the monolithic catalyst. Two kinds of alumina nanoparticles, α-alumina and γ-alumina, have no significant impacts on the Cu-SAPO-34 crystal structure, micropore morphology and catalytic activity. But washcoating experiments showed that the mass loss rate of the coating was less and the loading of the catalyst was higher when α-alumina was used as the binder. The reason of improving the adhesion and cohesion strength is the suitable thermal shrinkage, the uniform distribution and densification structure of α-alumina. Furthermore, optimization of the coating formulation with α-alumina as the binder has been performed. Finally, the catalyst prepared under the optimal conditions was tested by SCR and a maximum conversion rate of 97.4% was obtained. It was concluded that the use of the washcoating method with α-alumina does not affect catalytic performance while it increases bonding strength between substrate and catalysts.
研究领域:
化学工程
·
催化材料科学
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DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE
·
2020
·Vol. 56
·期 3
·2549-2558
·
IF 3.553
Liu Fangfang,Xu Zehua,Feng Ying,Li Yongfeng,Dou Yongshen,Liu Sanmao
In this work, we report a facile and economic one-step method under atmospheric pressure and 50 °C water bath for the fabrication of a three-dimensional (3D) upright-standing boehmite (AlOOH) nanosheet array film on a structured Al honeycomb substrate, in which zero-valence palladium (Pd 0 ) nanoparticles were well distributed at the same time. Redox reactions of two galvanic cells where the Al honeycomb substrate acted as the common anode, but the palladium precursor (Pd(NH 3 ) 4 2+ ) and weak base water (H 2 O + OH − ) served as the electrolyte of cathode I and II, respectively, led to simultaneous formation of Pd 0 nanoparticles at cathode I and AlOOH nanosheets at cathode II on the surface of Al substrate. The resultant AlOOH nanosheet array was uniform and about 300–400 nm thick, and the highly dispersed Pd 0 nanoparticles were also rather small with an average size of 8.4 nm. Hence, the as-obtained Pd-AlOOH/Al monolithic catalysts exhibited high specific surface area and large micro/mesopore structure as compared to pristine Al honeycomb substrate, leading to excellent catalytic activity in total oxidation reaction of toluene.
研究领域:
材料科学
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催化化学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Environmental Sciences
·
2021
·
IF 5.565
Xueyi Dong,Xihua Cao,Wenbin Jiang,Xiuxian Song,Zhiming Yu,Shitao Yu
Polyaluminum chloride modified clay (PAC-MC) is a safe and efficient red tide control agent that has been studied and applied worldwide. Although it is well known that the distribution of hydrolytic aluminum species in PAC affects its flocculation , little is known about the influence of particulars aluminum species on the microalgae removal efficiency of PAC-MC; this lack of knowledge creates a bottleneck in the development of more efficient MCs based on aluminum salts. The ferron method was used in this study to quantitatively analyze the distributions of and variations in different hydrolytic aluminum species during the process of microalgae removal by PAC-MC. The results showed that Al a , which made up 5%–20% of the total aluminum, and Al p , which made up 15%–55% of the total aluminum, significantly affected microalgae removal, with Pearson's correlation coefficients of 0.83 and 0.89, respectively. Most of the aluminum in the PAC-MC sank rapidly into the sediments, but the rate and velocity of settlement were affected by the dose of modified clay. The optimal dose of PAC-MC for precipitating microalgae was determined based on its aluminum profile. These results provide guidance for the precise application of PAC-MC in the control of harmful algal blooms .
研究领域:
环境科学
·
水处理工程
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产品关联
DOI
PubMed
高影响因子
WATER AIR AND SOIL POLLUTION
·
2021
·Vol. 233
·期 1
·1-9
·
IF 2.52
Yu Hui-Bo,Zhang Xian-Qiu,Han Xue,Yang Zhen-Zhen,Zhou Ya-Wen,Ding Wen,Du Ming-Xia
It is reported that residual aluminum from coagulation pretreatment can increase membrane fouling in nanofiltration (NF) or reverse osmosis (RO) desalination systems. However, the membrane fouling mechanism of residual aluminum and the effective control measures are not very clear. In this study, the nanofiltration membrane fouling caused by poly-aluminum chloride (PACl), the inhibitory effect of amino trimethylene phosphonic acid (ATMP) on aluminum foulants, and calcium carbonate scale in the presence of residual aluminum were investigated by permeate experiments and scanning electron microscopy (SEM) observation of the fouled membranes. Besides, the effect of adding ultrafiltration before nanofiltration on reducing membrane fouling caused by residual aluminum was also investigated. The results showed that most of the residual aluminum in feed eventually formed insoluble particles and fine flocs, and accumulated gradually on the membrane surface, which was a typical colloid particle fouling. ATMP can reduce the membrane fouling caused by residual aluminum to some extent, and the permeate flux ratio ( J/J c ) increased from 0.83 to 0.89 when ATMP increased to the optimal dose of 6 mg⋅L −1 . However, this means can still effectively eliminate carbonate scale, even in the presence of residual aluminum. Moreover, ultrafiltration pretreatment prior to nanofiltration was very effective to control membrane fouling, and the comprehensive cost was calculated to be only 0.006 $⋅m −3 . Therefore, the combined process of coagulation-ultrafiltration as a pretreatment of nanofiltration or reverse osmosis should be an ideal way to prevent membrane fouling caused by residual aluminum.
研究领域:
环境科学
·
水处理工程
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产品关联
DOI
高影响因子
JOURNAL OF POROUS MATERIALS
·
2016
·Vol. 24
·期 3
·679-683
·
IF 1.385
Li Xueai,He He,Ren Lili
The monolithic hydrophobic mesoporous alumina aerogels were successfully synthesized by acid–base sol–gel polymerization of aluminium chloride hexahydrate (AlCl 3 ·6H 2 O) in deionized water/alcohol solution (v/v = 3:7). To minimize shrinkage during drying, alumina hydrogels were aged in tetraethylorthosilicate (TEOS)/acetonitrile solution, and modified using trimethylchlorosilane (TMCS)/acetonitrile solution. Properties of the final product were examined by contact angle measurement, FTIR, FESEM, TEM and BET analyses. Surface modification was confirmed by FTIR spectroscopy. It was found that hydrophobic property of the alumina aerogels was affected by the contents of TMCS. When the molar ratio of TMCS to AlCl 3 ·6H 2 O is 0.35, hydrophobic alumina aerogels shows lower bulk density (0.453 g/cm 3 ) and higher surface area (495 m 2 /g) than those of unmodified alumina aerogels (0.933 g/cm 3 , 413 m 2 /g).
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
Journal of Materials Research and Technology-JMR&T
·
2020
·
IF 5.289
Deqing Zhu,Yuxiao Xue,Jian Pan,Congcong Yang,Zhengqi Guo,Hongyu Tian,Dingzheng Wang,Yue Shi
The alumina content of iron ores for sintering is gradually increasing with the growing depletion of high-grade iron ores, which is harmful to the sintering process. Therefore, it is essential to reveal the action mechanism of alumina on sinter quality. In this paper, the aluminum occurrence of various iron ores was determined by applying X-ray diffraction (XRD), optical microscopy, scanning electron microscopy and energy dispersive spectrum analysis (SEM-EDS). Then, the effects of iron ore type, aluminum occurrence (free alumina, gibbsite, diaspore, alumogoethite and kaolinite) and alumina content on formation characteristics of SFCA bonding phases as well as sinter matrix strength were investigated based on laboratory compact sintering tests. The results show that the discrepancy of aluminum occurrence contributes to different SFCA formation characteristics and then sinter matrix strength, due to different reactivity of various aluminum-containing minerals with iron oxides and fluxes. Increasing alumina content generally results in an increase in the porosity of sinters and deterioration of sinter matrix strength for all aluminum occurrence. Aluminum in the form of kaolinite is more conducive to form dendritic or acicular SFCA with superior sinter matrix strength compared with other aluminum occurrences. In contrast, aluminum occurring in free alumina presents greatest adverse impacts on sinter matrix strength due to its poor reactivity and high porosity of resultant sinters.
研究领域:
冶金工程
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
·
2020
·
IF 4.652
Yongchao Shan,Bowen Pu,Enzuo Liu,Chunsheng Shi,Chunnian He,Naiqin Zhao
For nanocarbon reinforced aluminum matrix composites (AMCs), the architecture design of reinforcements is an effective route to obtain superior mechanical performances. In this work, a novel AMC reinforced by CNTs wrapped with γ-Al 2 O 3 (CNTs@Al 2 O 3 ) reinforcement with balanced strength and toughness was fabricated by powder metallurgy methods. The wrapping structure of γ-Al 2 O 3 was synthesized through the in-situ reactions of Al matrix and boric acid decorated CNTs, thus improving the interface coupling of the composite. The CNTs@Al 2 O 3 /Al composite with the addition of 0.5 wt% CNTs and 10 wt% in-situ Al 2 O 3 exhibited a mean ultimate tensile strength of 404 MPa, which is significantly higher than unreinforced pure Al (183 MPa) and those reinforced by individual CNTs (207 MPa) or Al 2 O 3 (289 MPa). An improvement of ductility was also achieved in CNTs@Al 2 O 3 /Al composites compared with the Al 2 O 3 /Al composites with the same Al 2 O 3 content. The synergistic strengthening and toughening effects are ascribed to the ingenious in-situ CNTs@Al 2 O 3 wrapped structure, which highlights the importance of architecture design of reinforcements in AMCs, and sheds new light on the development of CNT-reinforced AMCs.
研究领域:
材料科学
·
力学
✓ 已验证
产品关联
DOI
高影响因子
CHEMOSPHERE
·
2022
·
IF 8.943
Yuqi Zhou,Hanqing Lv,Jin Lin,Tianyu Lv,Nan Wang,Heqing Tang,Lihua Zhu
This work reports a mechanochemical (MC) method for complete defluorination of perfluorooctanoic acid (PFOA) by using Al and Al 2 O 3 as milling agents. Both the Al/Al 2 O 3 molar ratio ( n Al / n Al 2 O 3 ) and the pre-thermal treatment of Al 2 O 3 strongly influenced the defluorination of PFOA. When commercial γ -Al 2 O 3 was pre-treated at 1200 °C, the use of Al and heat-treated γ -Al 2 O 3 with n Al / n Al 2 O 3 of 1: 1 led to PFOA defluorination of 100% after ball milling for 26 min at 350 rpm, being much higher than those (8.3%–58.1%) for using singlet milling agents or binary milling agents containing γ -Al 2 O 3 pre-heated at temperatures lower than 700 °C. It was clarified that the carboxylate-mediated adsorption of PFOA on Al 2 O 3 was essential for the MC decarboxylation as a degradation initiation step, and the in-situ generated electron on milled Al consequently caused the reductive dissociation of C–F bonds in the decarboxylation intermediate. A larger n Al / n Al 2 O 3 increased the in-situ electron generation rate ( r e ), and a higher heat-treatment temperature decreased OH − /H 2 O adsorbed on Al 2 O 3 to low the PFOA decarboxylation rate ( r dec ). The r e / r dec ratio determined defluorination pathways, and the percentage of the defluorination of PFOA in its total degradation including the generation of any degradation intermediates increased linearly with increasing r e / r dec .
研究领域:
环境科学
·
化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Journal of Cleaner Production
·
2022
·
IF 11.072
Liyu Chen,Jiaxin Yang,Yifan Zhang,Shaohua Wu,Youjian Yang,Wenju Tao,Zhaowen Wang
The synthesis of an Al–Zr master alloy in KF–AlF 3 –ZrO 2 molten salt by combining aluminothermic reduction and molten salt electrolysis processes was studied. The effects of reduction parameters such as stirring, reaction time, Al/ZrO 2 mass ratio and temperature on the Zr content and Zr recovery rate were studied and optimized. Under the optimal conditions of stirring, reaction time of 4 h, Al/ZrO 2 mass ratio of 3 and temperature of 960 °C, an Al–Zr master alloy can be obtained with a Zr content of 6.78 wt% and Zr recovery rate of 29.85%. The characterization results of the alloy show that the main phases contain Al and Al 3 Zr. And the Al 3 Zr appears as long rod-shaped or tetragonal shapes, which influenced by the Zr content and cooling rate. In addition, the reduced molten salt is electrolyzed to further extract Zr from the molten salt. The results show that the Zr remaining in the molten salt is completely recovered with a Zr recovery rate up to 94.72%. This two-step process is feasible for the large-scale extraction of Zr in molten salts to produce Al–Zr master alloys.
研究领域:
冶金工程
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）