CERAMICS INTERNATIONAL
·
2019
·
IF 3.45
Hang Liu,Shengqiang Song,Andrie M. Garbers-Craig,Zhengliang Xue
Cr 2 O 3 is a well-known corrosion resistant oxide used in refractory applications. However, it can oxidize into toxic and water-soluble Cr(VI) compounds upon reaction with calcium aluminate cement phases in the presence of oxygen, which subsequently causes disposal problems after use. This study describes the extent to which chromium in the spinel Mg(Al,Cr) 2 O 4 phase can be oxidized to Cr(VI) when it reacts with the calcium aluminate cement phases C 12 A 7 , CA, CA 2 and free CaO at 1300 °C in air, using XRD, XPS and leaching tests (TRGS 613 standard) as analytical tools. On reaction with CaO, the Mg(Al,Cr III ) 2 O 4 spinel mainly transformed into hauyne (Ca 4 Al 6 Cr VI O 16 ) and Ca 5 Cr 3 O 12 which contains both Cr(IV) and Cr(VI). The reaction of C 12 A 7 and CA with the spinel phase also resulted in the formation of Ca 4 Al 6 CrO 16 . Conversely, the reaction of Mg(Al,Cr III ) 2 O 4 spinel with CA 2 resulted in the formation of only a trace amount of Cr(VI). Water-soluble Cr(VI) leached in large quantities (>100 mg/L) from samples where the Mg(Al,Cr III ) 2 O 4 reacted with either C 12 A 7 or CA. Almost no Cr(VI) leached from the sample when Mg(Al,Cr III ) 2 O 4 reacted with CaO, using the standard TRGS 613 leach test, but a significant amount of Cr(VI) was released into solution when leached with a HCl solution for 12 h. Both Cr(IV) and Cr(VI) present in the Ca 5 Cr 3 O 12 dissolved into acidic solution. Only a small amount of Cr(VI) leached from the sample that resulted when spinel was reacted with CA 2 , even after a prolonged HCl leach. Cr(III) in spinel Mg(Al,Cr) 2 O 4 is very stable and does not leach in either distilled water or acidic solution.
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Journal of Materials Chemistry C
·
2018
·Vol. 6
·期 8
·2088-2094
·
IF 5.976
Xiran Shen,Xudong Yang,Chunyan Su,Jinghua Yang,Long Zhang,Binghui Liu,Siyu Gao,Fangyuan Gai,Zhubao Shao,Guanghui Gao
Stimuli-sensitive nanocomposites have received special attention because of their potential applications in various fields. In this work, we report a novel thermo-responsive photoluminescent silver clusters/hydrogel nanocomposite with red emission, as a probe for highly sensitive and selective detection of Cr(VI) in aqueous solutions. The hydrogel nanocomposites integrate the advantages of p(NIPAM-co-AAc) hydrogel submicron particles and Ag clusters: the p(NIPAM-co-AAc) hydrogel submicron particles can act as templates for Ag nanoclusters and exhibit thermo-responsive properties. In addition, Ag nanoclusters endow excellent photoluminescent properties to our nanocomposites, resulting in photoluminescent sensors. As a result, we obtained novel thermo-responsive Ag clusters/p(NIPAM-co-AAc) hydrogel nanocomposites through photoreduction process. The photoluminescence (PL) intensity of as-prepared nanocomposites exhibited a linear and reversible response from 2 to 85 °C and displayed a high PL quenching for the sensitive and selective detection of Cr(VI), rather than Cr(III). The limit of detection could reach as low as 1 ppb, which indicates that it is an ideal sensor tool for environmental monitoring, laboratory detections and various other applications.
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Nanomaterials
·
2018
·Vol. 8
·期 4
·263
·
IF 3.504
Jin Liu,Huihui Gan,Hongzhang Wu,Xinlei Zhang,Jun Zhang,Lili Li,Zhenling Wang
Porous hollow Ga2O3nanoparticles were successfully synthesized by a hydrolysis method followed by calcination. The prepared samples were characterized by field emission scanning electron microscope, transmission electron microscope, thermogravimetry and differential scanning calorimetry, UV-vis diffuse reflectance spectra and Raman spectrum. The porous structure of Ga2O3nanoparticles can enhance the light harvesting efficiency, and provide lots of channels for the diffusion of Cr(VI) and Cr(III). Photocatalytic reduction of Cr(VI), with different initial pH and degradation of several organic substrates by porous hollow Ga2O3nanoparticles in single system and binary system, were investigated in detail. The reduction rate of Cr(VI) in the binary pollutant system is markedly faster than that in the single Cr(VI) system, because Cr(VI) mainly acts as photogenerated electron acceptor. In addition, the type and concentration of organic substrates have an important role in the photocatalytic reduction of Cr(VI).Keywords:Ga2O3;porous;Cr(VI);organic pollutants
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PubMed
高影响因子
RSC Advances
·
2018
·Vol. 8
·期 49
·27623-27630
·
IF 2.936
Xiaoli Huang,Qi Hu,Lei Gao,Qirui Hao,Peng Wang,Dongli Qin
A metal–organic framework, MIL-101(Cr), was used to adsorb sulfamethoxazole (SMZ) in water and activated persulfate (PS) oxidation was investigated to regenerate SMZ-saturated MIL-101(Cr). Adsorption and oxidation were combined in this study. MIL-101(Cr) was characterized by SEM, BET, XPS and FT-IR analyses. Effects of various operating parameters on adsorption efficiency were studied. The dosages of persulfate for SMZ desorption and oxidation were investigated. The results showed that the recommended pH was 6–8 for SMZ adsorption and optimum MIL-101(Cr) dosage was 0.1 g L−1. SMZ adsorption by MIL-101(Cr) was a spontaneous process and nearly exothermic. Saturation adsorption capacity was achieved in 180 s and the adsorption followed the pseudo-second-order model. The maximum adsorption amount of MIL-101(Cr) to SMZ was 181.82 mg g−1 (Langmuir). MIL-101(Cr) also showed good adsorption capacities for sulfachloropyridazine (SCP), sulfamonomethoxine (SMM), and sulfadimethoxine (SDM). Persulfate was helpful for SMZ desorption from the surface of saturated MIL-101(Cr) and sufficient persulfate could simultaneously oxidize the SMZ. XPS analysis showed that the structure of MIL-101(Cr) was stable after the persulfate oxidation process. Regenerated MIL-101(Cr) had the same level of adsorption capacity as fresh MIL-101(Cr). An adsorption–oxidation combined process may be set up based on the results. This study provides basic data for the deep treatment of organic micropollutants in urban water bodies.
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高影响因子
Catalysts
·
2018
·Vol. 8
·期 9
·394
·
IF 3.465
Tian Zhao,Ming Dong,Ling Yang,Yuejun Liu
Nowadays, the controllable synthesis of stable hierarchical metal–organic frameworks (MOFs) is very important for practical applications, especially in catalysis. Herein, a well-known chromium–benzenedicarboxylate metal–organic framework, MIL-101(Cr), with a stable hierarchical structure, was produced by using phenylphosphonic acid (PPOA) as a modulator via the hydrothermal method. The presence of phenylphosphonic acid could create structural defects and generate larger mesopores. The synthesized hierarchical MIL-101(Cr) possesses relatively good porosity, and the larger mesopores had widths of 4–10 nm. The hierarchical MIL-101(Cr) showed significant improvement for catalytic activity in the oxidation of indene. Further, the presence of a hierarchical structure could largely enhance large dye molecule uptake properties by impregnating.Keywords:MIL-101(Cr);phenylphosphonic acid;hierarchical;enhanced catalytic activity;large molecule uptake
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Journal of the Taiwan Institute of Chemical Engineers
·
2017
·
IF 4.217
Ran Li,Qing-Da An,Bing-Qi Mao,Zuo-Yi Xiao,Shang-Ru Zhai,Zhan Shi
Employing mussel-inspired concept, a controllable “Sol-Gel-like” condensation of dopamine (DA) and aminosilane coupling agents (A1, A2, A3 represent APTMS, TSPED and TPDA, respectively) was undertaken to synthesize magnetic hollow composites (Fe 3 O 4 @A/PDA), aiming for removing Cr(VI) from wastewater. Compared to reported magnetic amino-functionalized composites for heavy metal removal, it is a new green process via post-grafting pathways that can avoid using organic solvents and high-temperature treatment. Structural characterization and batch experiments are correlated to illustrate the adsorption performance of resultant composites. Upon screening resultant adsorbents, Fe 3 O 4 @A2/PDA exhibited the highest adsorption capacity; the maximum Cr(VI) removal amount could be up to 284.1 mg g −1 at 298 K and pH 2.0. The pseudo-second-order and Langmuir model preferably fitted the adsorption process , besides, the activation energy is 7.17 kJ/mol −1 . The hollow composites could be easily separated from solutions by a magnet, and over 70% Cr(VI) could be removed even after five cycles. Electrostatic attraction and reduction reaction could be used to explain the adsorption mechanism that on the basis of XPS analysis. According to thermodynamic analysis, the adsorption is a spontaneous endothermic process. The high Cr(VI) adsorption capacity, fast adsorption kinetics and easy separation properties of hollow Fe 3 O 4 @A2/PDA composites make it be potential to alleviate Cr-containing aqueous solutions.
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CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
Sijing Yao,Jianqing Ma,Di Ma,Mika Erik Tapio Sillanpää,Minghua Zhou,Qing Ye,Huixia Jin,Kefeng Zhang
Chromium, as a widely utilized transition metal, presents wastewater with high toxicity and challenging treatment. To date, there has been limited exploration regarding the application of chromium in homogeneous Fenton-like reactions. This study aims to explore the potential of Cr(VI) and Cr(III) to activate hydrogen peroxide (H 2 O 2 ) and permonosulfate (PMS) for degrading coexisting pollutants in homogeneous solutions. The Cr(VI)/PMS system was found to be the most effective, with a 95.58 % removal efficiency for the azo dye Acid Red 73 (AR73). The Cr(VI)/H 2 O 2 system followed with 72.35 %, while the Cr(III)/H 2 O 2 and Cr(III)/PMS systems showed lower efficiencies at 25.65 % and 16.95 %, respectively. Various techniques were employed to delve into the mechanisms underlying chromium activation. The results indicate that both Cr(VI) and Cr(III) can activate H 2 O 2 to generate hydroxyl radical (HO • ). Moreover, Cr(VI) can activate PMS in the pH range of 3 ∼ 11, producing HO • , sulfate radical (SO 4 •- ), and singlet oxygen ( 1 O 2 ), while Cr(III) engages in chelation with PMS, causing the reaction to cease. Additionally, this study reveals that the chelating agent EDTA, upon complexing with Cr(III), efficiently activates PMS to generate 1 O 2 , and the mechanism behind EDTA-Cr(III) activation of PMS was elucidated through DFT calculations. An integrated evaluation of Cr performance in the Fenton-like reaction provides new research directions for the removal of pollutants from chromium-containing wastewater.
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Journal of Environmental Chemical Engineering
·
2024
·
IF 7.4
Haowen Zou,Wenqiang Xu,Shuaixuan Ying,Shichao Cai,Bo Chen,Ping Wang,Zhongkuan Wu,Feng He
Mechanochemically sulfidated microscale zero valent iron (S-mZVI bm ) exhibits promising Cr(VI) removal performance but is prone to be passivated by Cr(VI), how to mitigate the passivation is still a challenge. In this study, we successfully synthesized phthalic acid (PA, carboxyl-rich organic acid) modified S-mZVI bm particles (PA-S-mZVI bm (4:1)) through ball milling. The pre-corrosion of the ZVI surface by PA effectively increased the specific surface area of ZVI. Additionally, the carboxyl groups complexed with Cr(VI), thereby enhancing its Cr(VI) removal capacity and alleviating the passivation. The Cr(VI) removal by PA-S-mZVI bm (4:1) was mainly a chemisorption process on the surface and its Cr(VI) removal capacity (55.47 mg/g) was 1.26 and 9.94 – 14.83 times that of PA-mZVI bm and S-mZVI bm , respectively. The electron efficiency of Cr(VI) removal by both PA-S-mZVI bm (4:1) and S-mZVI bm was ∼100 %, however, the Fe(0) utilization efficiency of PA-S-mZVI bm (4:1) was at least 15 times higher than that of S-mZVI bm , explaining the superior performance of PA-S-mZVI bm (4:1). This study confirmed that PA modification could effectively mitigate the passivation and improve the Fe(0) utilization efficiency of S-mZVI bm .
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高影响因子
Journal of Water Process Engineering
·
2024
·
IF 6.3
Shuang Fu,Yingbo Chen,Xintong Wu,Liu Ye,Linzhe Xu,Xinyu Zhao
Nanofiltration (NF) membranes play a crucial role in wastewater treatment based on their unique separation mechanism. However, conventional polyamide nanofiltration membranes are susceptible to degradation in extreme pH or chlorine environments, resulting in a limited range of applications. In this study, hydrophilic functional coatings were constructed on polyethersulfone (PES) support using the biopolymer materials, κ-carrageenan (κ-CGN) and sodium carboxymethyl cellulose (CMC). The coatings were cross-linked with glutaraldehyde (GA) to form a dense three-dimensional network structure insoluble in water, enabling structural stability in harsh environments. The Na 2 SO 4 retention of the κ-CGN/CMC/PES composite membranes was maintained at 92.1 and 91.4 % after 38 days of immersion in 20 wt% H 2 SO 4 and 2 M NaOH aqueous solutions, respectively. Meanwhile, κ-CGN/CMC/PES maintained a good salt retention (Na 2 SO 4 , ∼90.0 %) after chlorine treatment (72,000 ppm h). The excellent separation performance of the κ-CGN/CMC/PES composite membranes at different pH and concentration of Cr (VI) indicated its wide application for Cr(VI) removal at harsh conditions.
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MICROCHIMICA ACTA
·
2016
·Vol. 183
·期 7
·2235-2240
·
IF 4.831
Yang Xiaoqing,Xia Yan
Mass spectrometry (MS) is the most powerful tool in phosphoproteomics research. However, phosphopeptides usually are present in low concentrations and their preconcentration therefore is highly desired. We describe a two-step method for the synthesis of a metal organic framework of the type MIL-101(Cr) that is modified with urea (then designated as MIL-101(Cr)-UR 2 ). It possesses large surface area, good solvent stability and high affinity for some phosphates. Due to the presence of modified urea functions, this material allows for selective and effective enrichment of phosphorylated peptides. It was successfully applied to the enrichment of phosphopeptides from non-fat-milk. The method was applied to the detection of phosphopeptides in a tryptic digest of β-casein where is showed a detection sensitivity as low as 10 −10 M.
A two step method was designed to synthesis MIL-101(Cr)-UR 2 and the prepared green solid was successfully applied to recognize phosphopeptides. (Amino functionalized metal-organic framework (MOF-NH 2 ); urea modified metal-organic framework (MOF-UR 2 ); matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS))
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JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2016
·
IF 3.782
Nannan Qin,Ya Zhang,Hongjian Zhou,Zhigang Geng,Gang Liu,Yunxia Zhang,Huijun Zhao,Guozhong Wang
The reactivity of zero valent iron (Fe 0 ) for removing Cr(VI) is self-inhibiting under neutral and alkaline conditions, due to the precipitation of ferrous hydroxide on the surface of Fe 0 . To overcome this difficulty, we incorporated a second metal (Co) into Fe 0 to form FeCo bimetallic nanoparticles (FeCo BNPs), which can achieve higher activity and significant improvement in the reaction kinetics for the removal of Cr(VI) compared with Fe 0 . The FeCo BNPs were synthesized by a hydrothermal reduction method without using any templates. The characterization analysis indicated that the products were highly uniform in large scale with 120–140 nm size in diameter. The obtained FeCo BNPs exhibited a remarkable removal ability for Cr(VI) in the pH range of 5.3–10.0. Especially, FeCo BNPs were able to reduce trace Cr(VI) (1.0 mg L −1 , pH = 7.5) down to about 0.025 mg L −1 within 1 h. XPS analysis confirmed that Cr(VI) was reduced to Cr(III) by FeCo BNPs, while Fe and Co was oxidized, implying a chemical reduction process. The enhanced removal of trace Cr(VI) could be originated from the introduction of Co, which not only served as a protecting agent against surface corrosion by galvanic cell effect, but also enhanced the efficient flow of electron transfer between iron and Cr(VI). All the results primarily imply that FeCo BNPs can be employed as high efficient material for wastewater treatment.
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高影响因子
INORGANICA CHIMICA ACTA
·
2017
·
IF 2.002
Jie Chai,Yanfei Liu,Jinglong Dong,Bin Liu,Binsheng Yang
The worldwide use of chromium(III) picolinate Cr(pic) 3 as nutrition additives has aroused more and more controversies. To reevaluate the safety and validity of Cr(pic) 3 , seven new derivatives Cr(R-pic) 3 (pic = picolinic acid, R = H ( 1 ), 5-Br ( 2 ), 5-CF 3 ( 3 ), 4-Cl ( 4 ), 5-COOH ( 5 ), 3-CH 3 ( 6 ), 5-OH ( 7 ), 3-OH ( 8 )) were synthesized and characterized by X-ray crystal diffraction, ESI-MS, IR and elemental analysis. It was found that different substituent group affected physicochemical activities of the complex such as the Fenton-like reaction and oxidation reaction. Especially, –OH group derivatives lose their hydroxyl radical-generation and Cr(VI)-generation abilities comparing with halogen group in tube experiment. Even so, these differences in chemistry properties may be ignored in live cells and animal tests: no obvious cellular damage (MTT assay) and tissue injury (acute toxicity study) were observed for both Cr(pic) 3 and its derivatives. In addition, hypoglycemic activity study indicated that these Cr(III) complexes have no significant influence than CrCl 3 salt on the blood glucose, serum insulin, total cholesterol, triglyceride, high density lipoprotein and low density lipoprotein of diabetic mice through two months’ study. Therefore, these substituent group is unable to improve the biological activities of Cr(pic) 3 obviously and the validity of Cr(pic) 3 used as a nutrition additives is doubted.
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