APPLIED CLAY SCIENCE
·
2020
·
IF 4.605
Xiaohai Liu,Baoguo Ma,Hongbo Tan,Li Gao,Pian Chen
Metakaolin (MK) is a widely used admixture in chloride immobilization which is conducive to the durability of reinforced concrete. In this study, triisopropanolamine (TIPA) was added into cement-MK system to improve the chloride immobilization by expediting the pozzolanic reaction of MK. The effect of TIPA on hydration of binder composed of 90% Portland cement and 10% MK was investigated, and the hydration behavior was characterized by thermogravimetric analysis , X-ray diffraction, nuclear magnetic resonance spectroscopy , and mercury intrusion porosimetry , based on the evaluation of pozzolanic reaction of MK by ion dissolution. Results indicated that TIPA promoted the hydration of both MK and cement, and chloride immobilization was also improved. The mechanism for the improvement was involved in three aspects: a) TIPA facilitated the dissolution of aluminum from MK to obtain more chloroaluminate salts, strengthening chemical binding; b) TIPA accelerated hydration of cement and MK for more C-S-H gel, conducive to the physical adsorption; c) TIPA increased the amount of hydrates to refine the pore structure , hindering the migration of chloride ion. This investigation provided one new method for improving the pozzolanic reaction of MK to enhance chloride immobilization of cement-MK system.
研究领域:
建筑材料学
·
化学工程
✓ 已验证
DOI
高影响因子
Journal of Building Engineering
·
2025
·
IF 7.4
Shaoxiong Ye,Pan Feng
Incorporating aluminum-rich materials to enhance intrinsic chloride binding capacity is critical for corrosion protection of reinforced concrete. This study investigated the impact of four chemical states of aluminum in aluminum-rich materials (sodium aluminate, aluminum hydroxide, hydrotalcite and alum) on the chloride binding capacity of cement paste mixed with chloride salts. Results demonstrated that the chemical state of aluminum significantly modulated chloride binding capacity: sodium aluminate, aluminum hydroxide, and hydrotalcite incorporation all enhanced chloride binding capacity though with diminishing early-stage enhancement effects, while alum incorporation reduced this capacity. Sodium chloride-prepared pastes consistently exhibited higher free chloride concentrations than magnesium chloride or calcium chloride counterparts across all curing ages and aluminum-rich materials at equal initial chloride ion concentrations. Aluminum-rich material's dissolution governed its hydration kinetics and chloride binding rates, constituting the key chloride binding mechanism in cement paste. These findings are expected to advance the design of highly durable cementitious materials for use in chloride-rich environments.
研究领域:
胶凝材料
·
混凝土腐蚀防护
·
无机化学
·
材料科学
·
建筑工程
✓ 已验证
产品关联
DOI
高影响因子
MATERIALS CHEMISTRY AND PHYSICS
·
2025
·
IF 4.7
Yankun Li,Airong Xu,Haitao Liu,Chu Cheng,Chen Chen,Kexing Song,Jing Tian,Yingang Guo,Weiwei Lu
In the process of fabricating high-purity copper, the high silver (Ag) content in copper plates poses a significant impurity issue, adversely affecting the quality and appearance of cathode copper, such as purity and surface finish. Moreover, it diminishes the electrolytic efficiency during production and escalates costs. This study successfully reduced the silver content in cathode copper from 7 g/t to 4.5 g/t by employing 1-aminopropyl-3-methylimidazolium chloride ([C 3 NH 2 CIm][Cl]) as an single yet multifunctional additive to regulate the copper electrolytic refining process, thereby enhancing the purity of the cathode copper. The cathode copper products and anode slime prepared were characterized and analyzed using techniques such as SEM, XRD, and XPS. The findings indicated that [C 3 NH 2 CIm][Cl] exerts a flocculation effect on anode slime during electrolysis, mitigating the adhesion and inclusion of suspended anode slime in cathode copper. Furthermore, the silver decreasing efficacy of [C 3 NH 2 CIm][Cl] in the copper electrolytic refining process was investigated through electrochemical characterization. It was observed that [C 3 NH 2 CIm][Cl] can react with Ag + to form precipitates, thereby reducing the concentration of Ag + in the solution. Additionally, [C 3 NH 2 CIm][Cl] can complex with Ag + , elevating the electrode potential of Ag + during the electrolytic refining process, making it less likely for Ag + to be reduced at the cathode under comparable conditions. This research provides an effective additive strategy for improving the purity and production efficiency of copper.
研究领域:
冶金学
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电化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
WASTE MANAGEMENT
·
2025
·
IF 7.1
Dongping Song,Tao Huang,Xiaolong Sun,Yun Xia,Chong Luo,Jialin Cui,Kai Chen,Weihua Liu,Jie Ren
The poor pozzolanic activity and high alkalinity of municipal solid waste incineration fly ashes (MSWI-FA) would deteriorate the stability of the MgO-SiO 2 -H 2 O (M−S−H) binder system, further inhibiting the treatment capacity of cement to wastes. In this study, sulfhydryl-functionalized graphene oxide nanoparticles (SFG) were synthesized and incorporated into the MSWI-FA-blended M−S−H (MSH-MSWI-FA) system to strengthen the solidification/stabilization (S/S) of both heavy metals (HMs) and chloride salts in the matrix and mechanical stability of cement. The linear increases in nanomaterials (from 0.5 % to 2.5 %) and MSH (from 40 % to 80 %) both decreased the concentrations of HMs and Cl anions leached from the solidified cubes in the MSH-MSWI-FA cementation. The least leaching concentration of Zn, Cu, Pb, Cd, Cr, and Cl were 0.0046 mg/L, 0.0032 mg/L, 0.014 mg/L, 0.00068 mg/L, 0.030 mg/L, and 0.36 g/L from the SFG-MSH-MSWI-FA cemented samples, respectively. The incorporation of graphene oxide nanoparticles (NGO) and SFG elevated the residual moieties of HMs, enhanced the mechanical strength and acid resistance, and improved the microstructural properties of MSH-MSWI-FA cementation. SFG played a more dominant role in the enhancement than NGO. Sulfhydryl-functionalization for nanomaterials intensifies the improvement process. The minerals including M−S−H, CaO-SiO 2 -H 2 O (C-S-H), and Phase-5 were formed in the MSH-MSWI-FA cement. Silica fume (SF), lightly burnt magnesia (CC-MgO), and MSWI-FA reacted with each other in a ternary system, which induced the self-alkali-activated cementation of C-S-H, M−S−H, and magnesium oxychloride (MOC) cement.
研究领域:
环境科学
·
材料科学
✓ 已验证
DOI
PubMed
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2025
·
IF 13.2
Dongping Song,Tao Huang,Kai Chen,Jialin Cui,Qingyang Xu,Chengyu Yan,Chengzhe Yang,Shaohang Wan,Minfeng Tao
In this study, the magnesium phosphate cement (MPC) coupling with graphene nanosheets (GNP) was employed to solidify municipal solid waste incineration fly ashes (MSWI-FA) and stabilize the contaminants of heavy metals (HMs) and chloride salts in the matrix. The maximum compressive strength of 45.62 MPa and the minimum leaching concentration of 0.012, 0.0064, 0.00079, 0.0045, and 0.048 mg/L for Zn, Cu, Cd, Pb, and total Cr and 0.86 g/L for chloride were obtained from the GNP-MPC-MSWI-FA-cemented matrix in the orthogonal tests and toxicity-leaching experiments, respectively. MSWI-FA significantly changed the MPC hydration process. The influence of MPC on the speciation transformation of HMs was more prominent than that of GNP. Fick's theory model was appropriate in fitting the whole leaching process of HMs and dissolvable chloride species from the matrix under acid-immersion conditions. Both K-struvite and Phase-5 were formed in the matrix in mineral analysis, verifying the formation of both MPC and magnesium oxychloride cement (MOC). The chloride salts in the MSWI-FA facilitated the self-cementation of MOC from light-burnt magnesia in MPC. The mechanisms including the formation of phosphate precipitation, gelation encapsulation, and chemical hydration brought by MPC attributed to effective solidification/stabilization of HMs and chloride in the MSWI-FA.
✓ 已验证
产品关联
DOI
高影响因子
CELLULOSE
·
2021
·Vol. 28
·期 7
·4025-4037
·
IF 5.044
Gao Xiaoru,Yu Yuxiu,He Qian,Li Haojie,Liu Yaodong
A sustainable natural polymer, cellulose, has been used as precursor for producing carbonaceous materials. Ionothermal carbonization (ITC) in ionic liquid (IL) could transform biomass into functional carbon materials at a relatively low temperature. In order to improve the ITC carbon yields and structures, the first raw transition metal chlorides were added into IL, 1-Butyl-3-methyl-imidazole chloride (BmimCl), and their catalyzing effects were compared. It is found that the catalyzing effects of transition metal chlorides are mainly correlated to their cation size. With the addition of 0.5wt% NiCl 2 (based on IL), a high carbon yield of 94wt% is obtained. Additionally, the bio-based carbonaceous materials exhibit a higher graphitization degree with the addition of metal chloride. Furthermore, the IL shows good cyclability, and the carbon yield remains to be higher than 80 wt% after 5 cycles.
研究领域:
材料科学
·
化学工程
·
可持续化学
✓ 已验证
DOI
高影响因子
Journal of Environmental Sciences
·
2019
·
IF 3.556
Shijin Dai,Yilin Zheng,Youcai Zhao,Yu Chen,Dongjie Niu
Hazardous waste dechlorination reduces the potential of creating dioxins during the incineration process. To investigate the salt effect on waste dechlorination, molten hydroxides with a low melting temperature were utilized for the pre-dechlorination and decomposition of chlorine-containing organic wastes (COWs) including trichlorobenzene (TCB), perchloroethylene , hexachlorobenzene and chlordane . The results showed that a eutectic mixture of caustic sodium and potassium hydroxides (41 wt.% NaOH and 59 wt.% KOH) led to a low melting point below 300°C and a relatively high chlorine retention efficiency (CRE) with TCB as a representative COWs. The amounts of hydroxides, reaction time, and temperature all had notable influence on CRE. When the mass ratio of hydroxides to TCB reached 30:1, approximately 98.1% of the TCB was destroyed within 2.5 hr at 300°C with CRE of 71.6%. According to the residue analysis , the shapes of reaction residues were irregular with particles becoming swollen and porous. The benzene ring and C–Cl bonds disappeared, while carboxyl groups formed in the residues. The stripped chlorine was retained and condensed to form chloride salts, and the relative abundance of the chloride ions associated with the mass of TCB in residues increased from 0 to 75.0% within the 2.5 hr reaction time. The observed concentration of dioxins in residues was 5.6 ngTEQ/kg. A reaction pathway and possible additional reactions that occur in this dechlorination system were proposed. Oxidizing agents may attack TCB and facilitate hydrogenation/dechlorination reactions, making this process a promising and environmentally friendly approach for chlorine-containing organic waste treatment .
研究领域:
环境科学
·
化学工程
·
废物管理
✓ 已验证
产品关联
DOI
PubMed
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2015
·
IF 2.587
Xueqin Zhang,Mingjie Chen,Huihui Wang,Chuanfu Liu,Aiping Zhang,Runcang Sun
In this study, xylan-graft-polycaprolactone (xylan-g-PCL) with different degrees of substitution (DS) and degrees of polymerization (DP) were prepared by homogeneous ring-opening graft polymerization (ROGP) of ε-caprolactone (ε-CL) onto xylan in ionic liquid (IL) 1-allyl-3-methylimidazolium chloride ([Amim]Cl) using 4-dimethylaminopyridine (DMAP) as catalyst. FT-IR, 1D (1H and 13C NMR) and 2D NMR (1H–13C HSQC and HMBC) spectra provided the evidence of the occurrence of ROGP reaction. 1H–1H COSY confirmed the correct assignment of the proton signals. HSQC also indicated that 38.78% and 61.22% of PCL side chains were attached to C2 and C3 positions of anhydroxylose units, respectively. Xylan-g-PCL copolymers were further characterized by TGA/DTG, SEM, and XRD. The results indicated that the thermal stability of xylan increased upon the DMAP-catalyzed ROGP reaction in [Amim]Cl, and the surface morphologies were significantly changed with increased DS.
研究领域:
高分子科学
·
材料科学
·
分析化学
·
物理化学
✓ 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）