查找使用阿拉丁产品的科研文献

Magnetic solid phase extraction for the determination of Pb(II) and Cd(II) in high salt foods

Dian-Bing Zhou,Hai-Tao Zhu,Yu-Zhu Hou,Gui-Lan Shen,Can Shi,Ya-Jie Zhu,Ya-Bing Xiao,Wei Song,Yu-Xin Liu,Fang Han,Ping Zheng,Xiao-Feng Yu

The conventional method for the determination of heavy metals in food is acid digestion followed by atomic absorption spectrometry or induced coupled plasma mass spectrometry . However, for high salt foods, due to the strong matrix effect, the detection results are seriously inaccurate. In this work, sulfur-functionalized magnetic metal-organic frameworks (Fe 3 O 4 @UiO-66-SH) were synthesized by coating Fe 3 O 4 nanospheres with sulfydryl-functionalized UiO-66. The Fe 3 O 4 @UiO-66-SH possesses both the magnetic properties of Fe 3 O 4 and the diverse properties of metal-organic framework (MOF) in one material, which has the superiority of high surface area, easy-operation and strong adsorb ability with Pb (II) and Cd(II), is used to separate and determine Pb (II) and Cd(II) in high salt foods by magnetic solid phase extraction-induced plasma mass spectrometry. The detection limits (LODs) for Pb (II) and Cd(II) were 0.17 and 0.21 µg/kg, respectively, and the quantification limits (LOQs) were 0.56 and 0.66 µg/kg. Analyzing the certified reference material of soy sauce (CFAPA-QC1728–4, P41839) and estimating the spiked recoveries proved the accuracy and precision of the proposed method. The determined values agreed well with the reference values, and the recoveries for spiking sample varied from 85.8–100.5%.

Organosilicon-Mediated Cadmium Uptake, Transport, and Detoxification in Rice: Comparison Between Low-Cd and Conventional Rice Varieties

Cadmium (Cd) contamination in rice threatens rice food safety. Organosilicon shows substantial potential to reduce the uptake and accumulation of Cd in crops. However, the current understanding of the mechanisms by which organosilicon reduces Cd toxicity in rice remains fragmented. In a one-season pot experiment using soil with a total Cd concentration of 1.04 mg·kg−1, we examined organosilicon-modulated physiological responses and Cd-transport gene expression in two rice varieties. The three organosilicon compounds tested were KH590 (3-mercaptopropyltrimethoxysilane), DMDCS (dimethyldichlorosilane), and D6 (dodecamethylcyclohexasiloxane). Two-way ANOVA confirmed significant cultivar × treatment interactions for Cd in all organs (p< 0.05). DMDCS treatment reduced grain Cd in Shaoxiang 100 by about 43.4%. Subcellular fractionation revealed that DMDCS enhanced Cd sequestration in root and culm cell walls (60.8% increase in culm), while D6 and KH590 showed greater efficacy in leaves. Gene expression analysis indicated that KH590 most potently suppressed the root uptake gene OsNramp5 (76% reduction), whereas DMDCS and D6 exerted stronger inhibition on the long-distance transport gene OsLCT1 (up to 91.8%). Principal component analysis further confirmed that KH590 primarily inhibited root uptake, DMDCS mainly enhanced root Fe oxide deposition and culm Cd retention, while D6 best maintained biomass and reduced late-stage Cd transport to grains, increasing yield by 28%. These findings provide evidence for differential pathways through which organosilicon compounds mitigate Cd stress in rice under pot conditions, offering a theoretical reference for reducing Cd pollution in farmland.

Coexistence of microplastics and Cd alters soil N transformation by affecting enzyme activity and ammonia oxidizer abundance

Ting Lan,Xiaoman Dong,Shuang Liu,Minghua Zhou,Yang Li,Xuesong Gao

Interactions between heavy metal and microplastics represent a serious threat to ecosystems and human health, but the effect of their coexistence on the soil N transformation processes is unclear. The mechanism in which metal-polluted soil reacts to additional microplastics stress and their toxicology interactions on soil N transformation were determined by investigating the dynamics of soil microbial N transformation in response to Cd stress and different doses of polythene (PE) microplastics by conducting a 14 days aerobic 15 N microcosmic incubation experiment. The gross nitrification rates ( n _gross ) were decreased by 7.47% and 12.5% in the 1% and 2% ( w / w ) PE groups, respectively, through the direct effect on enzyme activity (β-glucosidase, N-acetylglucosaminidase, and leucine-aminopeptidase) and the abundance and community composition of ammonia oxidizer . It also exerted indirect effect by reducing nitrification substrate concentrations. PE microplastics (>1% [ w / w ]) significantly increased the gross N immobilization rate, and this change could have been driven by C/N stoichiometry . Cd stress alone led to a rapid short-term mineralization–immobilization turnover (1.67 times of the control). However, such effect was offset when Cd coexisted with PE microplastics, possibly because Cd was directly adsorbed by PE microplastics, and/or microplastics satisfied the C demand by microorganisms under Cd stress. Our findings demonstrated that the coexistence of microplastics and Cd significantly altered soil N nitrification and immobilization, which would change the N bioavailability in soil and alter the effect N cycling on the ecological environment.

Double Type-II Heterojunction MnS/Mn–Cd–S/Ni-Polyoxometalate for Improving Visible-Light-Driven H2 Production

Yuqing Hu,Puhui Deng,Wenying Wang,Linping Zhang,Yu Hou

Element doping and collaboration with other cocatalysts are two vital strategies to improve the photoelectrochemical properties and overcome the drawbacks of CdS for better photocatalytic performance. In this work, a series of manganese cadmium sulfides (MnxCd1–xS) were obtained by a solvothermal method. When x is equal to or greater than 0.3, MnxCd1–xS is composed of Mn–Cd–S sosoloid and MnS. Among all these MnxCd1–xS products, the Mn0.5Cd0.5S sample showed the best photocatalytic hydrogen production (5.99 mmol g–1 h–1). To further elevate the hydrogen production rate of Mn0.5Cd0.5S, four kinds of Ni-POMs were coupled with it as cocatalysts, and all these composite photocatalysts displayed enhanced performance. The highest efficiency was observed for 15-Ni4–Mn0.5Cd0.5S, which is up to 36.58 mmol g–1 h–1. Various characterizations indicated that Ni4P2W18, Mn–Cd–S sosoloid and MnS in the 15-Ni4–Mn0.5Cd0.5S composite form a double type-II heterojunction, which facilitates the separation and transfer of photogenerated carriers.

Studies on Structure, optical and magnetic properties of Cd, Zn, Mn and Co complexes of terpyridine ligand

Qiang Zhao,Qi-Yang Li,Zhi Shen,Guo Zang,Wen-Jun Lv

In order to further enrich the research on the synthesis of complexes with terpyridine ligand and transition metals, in this work, 4′-(4-(1H-imidazol-1-yl)phenyl)-2,2′:6′,2′'-terpyridine (Iptpd), 1,2-benzenedicarboxylic acid (1,2-BA) were used to construct metal complexes with Cd 2+ , Zn 2+ , Mn 2+ and Co 2+ by solvothermal reaction, and five complexes were constructed, namely, [Cd(Iptpd)(NO 3 ) 2 ] n ( 1 ), [Mn(Iptpd)(NO 3 ) 2 ] n ( 2 ), [Zn(Iptpd) (NO 3 ) 2 ·2H 2 O] n ( 3 ), [Mn(Iptpd)(1,2-BA)] 2 ( 4 ) and [Co 3 (Iptpd) 2 (1,2-BA) 2 (NO 3 ) 2 ·10H 2 O] n ( 5 ); Single crystal x-ray diffraction analyses reveal that complexes 1, 2, 3 and 5 have one-dimensional chain structure, 4 is a binuclear structure. In addition, Luminescence behavior of complexes 1 and 3 , magnetic properties of complexes 2 and 4 were investigated. The fluorescent test result shows that complex 1 and 3 have weak fluorescence performance and the fluorescence intensity is lower than that of ligand; The magnetic results indicate that complex 2 has ferromagentic property and 4 has antiferromagentic property.

Simultaneous and continuous stabilization of As and Cd in contaminated soil by a half wrapping-structured amendment

Danna Shan,Yan Shi,Bin Zhou,Zilin Liu,Liu Yang,Xuetao Zhu,Qishi Luo,Guanghe Li

A simple and convenient method was used to prepare a novel granular half wrapping-structured amendment (HWA) for stabilization of both cationic and anionic heavy metals. By coating Ca(OH) 2 with silicate minerals to obtain the core-coating wrapping balls, followed by drying and mixing with FeSO 4 , the final HWA effectively prevented the reaction of FeSO 4 with Ca(OH) 2 and exihibited high stabilization of arsenic (As) and cadmium (Cd) in the contaminated soils simultaneously and continuously. XRD, FTIR and SEM characterization showed that Ca(OH) 2 was successfully wrapped by zeolite without changing their chemical properties. The amendment illustrated relatively fast stabilization for As and Cd, and the stabilization rate by HMA prepared at FeSO 4 ·7H 2 O: zeolite: Ca(OH) 2 = 6.5:1:1 was 95.5% for As and 94.6% for Cd, much higher than the compound material (CM) which had side effect on Cd stabilization. In the effect of storage time experiment, when HWA was stored from 0 day to 365 days, the stabilization rate of As and Cd by HWA just decreased 3.4% and 4.3%, respectively. While the addition of CM to the soil reduced the As stabilization rate from 91.1% to 87.1% and the Cd stabilization rate was reduced from −139.8% to −223.1%. The long-term soil stabilization study demonstrated that HWA could decrease the concentration of extricable As and Cd simultaneously and continuously for 365 days without notable changes in soil pH. This research develops an easy method to synthesize granular HWA for the stabilization of cationic and anionic heavy metals from the actual contaminated soils.

An ink-jet printed dual-CD ratiometric fluorescent paper-based sensor for the visual detection of Cu2+

Ying Li,Fei Lu,Qing-zhi Li,Yi-hua Zhou,Jun Qian,Sheng Cao,Chen-yu Wang

Copper ion (Cu2+) plays an important role in the human body because it is beneficial for metabolism. However, an excessive or slight amount of Cu2+ can cause various symptoms. Therefore, it is necessary for human health to realize the trace and visual detection of Cu2+. Referring to traditional fluorescence test papers, the qualitative and semi-quantitative detection of Cu2+ could be realized by a dual-carbon dots (CDs) ratiometric fluorescent paper-based sensor with the advantages of environmental protection, portability and low cost. In this paper, the inkjet-printed test paper with the best mixing ratio of the two CDs has been researched to maximize the spectral energy transfer of ion detection (maximum color gamut expansion). Among them, the preparation method of b-CDs has been improved, increasing the photoluminescence quantum yield (PLQY) to 88.9%. The sensitivity detection limit of the double emission ratio sensor was 0.15 nM in solution, and the human eye can distinguish at least 3 μmol L−1 Cu2+ in the paper-based sensor. Compared with the traditional single-emission sensor, the human eye was more sensitive to the color change of the emission ratio sensor. The results indicate that we not only realized the micro detection of Cu2+ with convenient methods, but also provided a promising strategy for the visual detection of Cu2+.

Cu(II) and Cd(II) capture using novel thermosensitive hydrogel microspheres: adsorption behavior study and mechanism investigation

Jianxin Tang,Jianmin Huang,Thein Tun,Sihua Liu,Jue Hu,Guiyin Zhou

BACKGROUND At present, various kinds of hydrogel adsorbents are applied to the treatment of heavy metal ions in wastewater. In this work, we focused on the adsorption of cadmium [Cd(II)] and copper [Cu(II)] onto microspheres of a novel thermosensitive hydrogel (NH 2 -SA/PNIPA, aminated sodium alginate/poly- N -isopropyl acrylamide), studied the effect of temperature on the phase transition of the hydrogel in detail, and discussed the influence on the adsorption behavior of metal ions in the hydrogel. RESULTS The NH 2 -SA/PNIPA exhibited a higher adsorption efficiency under the conditions of interfering monovalent cationic and neutral pH. The adsorption capacities based on the Langmuir model were 57.2 mg g –1 for Cu(II) and 100.5 mg g –1 for Cd(II) at 20 °C, respectively. Higher temperature facilitated the adsorption process and also led to the volume shrinkage and hydrophobicity of NH 2 -SA/PNIPA. The metal ions had different hydration and hence different adsorption capacities, of 56.7 mg g –1 for Cu(II) and 88.6 mg g –1 for Cd(II) at 40 °C. The results of diffusion behavior analysis showed that the diffusion coefficients were ≈1 × 10 −11 m 2 s –1 . The adsorption performance of NH 2 -SA/PNIPA hardly decreased even after five cycles. In addition, the adsorption process was controlled mainly by the complexation reaction. CONCLUSION The novel hydrogel microspheres overcame the deficiency of conventional adsorbents and possessed high diffusibility. This work provides a theoretical basis and empirical evidence for enhancement of adsorbents for removing heavy metals in wastewater. © 2021 Society of Chemical Industry (SCI).

Phosphate modified magnetite@ferrihydrite as an magnetic adsorbent for Cd(II) removal from water, soil, and sediment

Haoyang Fu,Hongfei He,Runliang Zhu,Lan Ling,Weixian Zhang,Qingze Chen

This work successfully fabricated a novel magnetic adsorbent, i.e., phosphate modified magnetite@ferrihydrite (Mag@Fh-P), and explored its potential application for Cd(II) removal from water, soil, and sediment. To synthesize the adsorbent, ferrihydrite-coated magnetite (Mag@Fh) was firstly developed with partially acid-dissolved natural magnetite particles, followed by in-situ synthesis of ferrihydrite on magnetite surface via alkali addition. Selection of natural magnetite as iron source for ferrihydrite synthesis and as magnetic core is believed to save the cost of adsorbent. Then, phosphate was loaded on Mag@Fh by impregnation-heating treatment to produce Mag@Fh-P. Batch adsorption experiments revealed that the Cd(II) adsorption on Mag@Fh-P could reach equilibrium within 60 min, and the calculated adsorption capacity using Langmuir model was 64.1 mg/g, which was significantly higher than that on magnetite (0.44 mg/g) and Mag@Fh (23.9 mg/g). The results from X-ray photoelectron spectroscopy analysis and batch adsorption experiments confirmed that both ligand exchange and electrostatic attraction contributed to Cd(II) adsorption. Besides, Mag@Fh-P can also be an efficient amendment for soil and sediment remediation. The spent Mag@Fh-P could be easily recovered via magnetic separation, accompanied by the significant decrease in total Cd(II) concentration in soil/sediment. At an adsorbent dosage of 2 wt%, 0.82 and 0.74 mg/kg of total Cd(II) in soil and sediment was removed, respectively. In all, the synthesized Mag@Fh-P as adsorbent has the merits of cost effectiveness, fast adsorption rate, high adsorption capacity, and easy separation, and thus it has promising application for the removal of heavy metal cations from water, soil, and sediment.

Evaluation of Different Types and Amounts of Amendments on Soil Cd Immobilization and its Uptake to Wheat

Zhou Changrui,Yuan Haiyan,Ning Chuanchuan,Li Shuailin,Xia Zhuqing,Zhu Mengmeng,Ma Qiang,Yu Wantai

Using amendments is a cost-effective method to soil cadmium (Cd) remediation, whereas knowledge about how different amendments and rates affect remediation efficiency remains limited. This study aimed to evaluate the impacts of different types and amounts of amendments on soil Cd immobilization and its uptake by plants. Biochar (BC), zeolite (ZE), humic acid (HA), superphosphate (SP), lime (L), and sodium sulfide (SS) were applied at three rates (low, medium, and high) ranging from 0.5 to 5%. The concentration of CaCl 2 -extractable Cd was considerably affected by the amendments, except HA, and the high doses achieved better immobilization effects than the low doses did. The addition of amendments decreased weak acid soluble Cd by 4.1–44.0% but slightly increased the fractions of oxidizable and residual Cd. These amendments (except BC and HA dose of 1%) decreased Cd accumulation in grains by 1.3–68.8% and (except SP) in roots by 16.3–65.5% compared with the control. The SP efficiently immobilized Cd but posed a potential soil acidification risk. Moreover, SS treatment increased the soil electrical conductivity (EC) value and restricted the growth of wheat, possibly due to high-salt stress. BC, ZE, and L exerted significant effects on the reduction in available Cd as the application rate increased. These amendments enhanced Cd immobilization mainly by changing Cd availability in soil and influencing its redistribution in different fractions in soil and root uptake by plants. This study concluded that BC-5%, ZE-1%, and L-0.5% can be used for Cd immobilization in acidic or neutral soils.

PtNPs-GNPs-MWCNTs-β-CD nanocomposite modified glassy carbon electrode for sensitive electrochemical detection of folic acid

Yuan Meng-Meng,Zou Jiao,Huang Zhao-Ning,Peng Dong-Ming,Yu Jin-Gang

A novel electrochemical sensor, platinum nanoparticles/graphene nanoplatelets/multi-walled carbon nanotubes/β-cyclodextrin composite (PtNPs-GNPs-MWCNTs-β-CD) modified carbon glass electrode (GCE), was fabricated and used for the sensitive detection of folic acid (FA). The PtNPs-GNPs-MWCNTs-β-CD nanocomposite was easily prepared with an ultrasound-assisted assembly method, and it was characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The electrochemical behavior of FA at PtNPs-GNPs-MWCNTs-β-CD/GCE was investigated in detail. Some key experimental parameters such as pH, amount of PtNPs-GNPs-MWCNTs-β-CD composite, and scan rate were optimized. A good linear relationship ( R 2  = 0.9942) between peak current of cyclic voltammetry (CV) and FA concentration in the range 0.02–0.50 mmol L −1 was observed at PtNPs-GNPs-MWCNTs-β-CD/GCE. The detection limit was 0.48 μmol L −1 (signal-to-noise ratio = 3). A recovery of 97.55–102.96% was obtained for the determination of FA in FA pills (containing 0.4 mg FA per pill) at PtNPs-GNPs-MWCNTs-β-CD/GCE, indicating that the modified electrode possessed relatively high sensitivity and stability for the determination of FA in real samples. Graphical abstract

Effects of fulvic acid and montmorillonite colloids at different concentrations on Cd(II) sorption onto nano-hydroxyapatite

Mengmeng Wu,Limei Mo,Erping Bi

Natural colloids can influence the binding mechanisms between nano-hydroxyapatite (nHAP) and Cd(II). In this study, the effects of organic and inorganic natural colloids on Cd(II) sorption onto nHAP were compared. Different experimental approaches combined with the additivity model and the Extended-Derjaguin-Landau-Verwey–Overbeek model were used to quantify the distribution of Cd(II) in the systems of nHAP and natural colloid, and the interaction energy between particles. The results showed that both fulvic acid (FA) and montmorillonite colloid (MONT) had the promotion and inhibition effects on Cd(II) sorption onto nHAP. Coexistence of FA or MONT could stabilize nHAP particles. FA could adsorb onto nHAP particle surface via carboxylic and phenolic groups, which increased nHAP electronegativity and formed steric resistance effect. Coexistence of MONT mainly increased nHAP electronegativity. These effects prevented the reduction of the specific surface area of nHAP particles and increased the Cd(II) sorption onto nHAP. However, the inhibition effect on Cd(II) sorption was enhanced with increasing concentration of FA or MONT because more soluble FA-Cd or suspended MONT-Cd complexes formed in the system. In nHAP-FA-Cd systems, the Cd(II) sorption onto FA was well predicted but that onto solid phase was underestimated by the additivity model. In nHAP-MONT-Cd systems, Cd(II) sorbed onto mixtures of nHAP and MONT was well described by the additive model. The findings of this study can help to understand the fate of Cd(II) in natural water and soil.