查找使用阿拉丁产品的科研文献

Effects of virgin microplastics on the transport of Cd (II) in Xiangjiang River sediment

Yougong Li,Ming Chen,Jilai Gong,Biao Song,Maocai Shen,Guangming Zeng

River sediments are considered as sinks of microplastics (MPs). Although numerous studies have been conducted on MPs pollution in river sediments, the impact of MPs on the environmental behavior of Cd (II) in river sediments is still unknown. In this work, the effects of six MPs (polyethylene, polypropylene , polystyrene , polyvinyl chloride , polymethyl methacrylate and polylactic acid) on the adsorption of Cd (II) by Xiangjiang River sediment and the transport of Cd (II) in sediment were studied. The results showed that the adsorption ability of sediment to Cd (II) decreased with the increase of the content of MPs in sediment. When the content of MPs in sediment increased to 10%, polypropylene had the greatest effect on the adsorption affinity of sediments to Cd (II). Moreover, the addition of MPs accelerated transport of Cd (II) in sediment, and the transport of Cd (II) in sediment increased with the increase of the content of MPs. The reason may be that after adding MPs, the adsorption capacity of sediment to Cd (II) decreases, and the mass transfer resistance of Cd (II) to sediment reduces, which leads to faster transport of Cd (II) in sediment. Especially, when the content of MPs in sediment increased to 10% (w/w), the saturation point of the breakthrough curve decreased by about 70 pore volumes. This work hopes to provide helpful views on the environmental behavior and risk assessment of Cd (II) in the presence of MPs.

Contribution of nitrogen configurations to the adsorption of Cd(II) in nitrogen-enriched biochar

Yu Jiang,Chen Yang,Qian Yao,Yurong Deng,Jingjing Yang,Yanjun Liu,Zhuozhi Ouyang,Weilin Huang,Zhi Dang

To clarify the function of the nitrogen-containing structures on the adsorption of heavy metals, nitrogen-enriched biochars (NBCs) mainly composed of pyrrolic, pyridinic, and graphitic nitrogen were prepared to investigate the interaction mechanism with Cd(II). The results of batch experiments revealed that the saturated Cd(II) adsorption capacities of Pr-NBC, Pd-NBC, and Gp-NBC were 12.68, 24.04, and 35.95 mg g−1 respectively. The strongest adsorption ability was found for the Gp-NBC and was ascribed to the enhancement of graphitic nitrogen. The results from SEM-EDS and XRD, and the zeta potentials for the materials revealed that carbonate precipitation, cation exchange, and electrostatic interactions contributed to the adsorption of Cd(II). XPS and FTIR demonstrated that nitrogen in the carbon framework might have promoted the adsorption by forming cation–π interactions between graphitic nitrogen and Cd(II). The electrostatic potential distribution of the nitrogen with different configurations fully confirmed this. The theoretical calculations also proved that graphitic nitrogen had the lowest interaction energy to Cd(II), which further verified the strong contribution of graphitic nitrogen to the adsorption of heavy metal. Nitrogen-enriched biochar effectively adsorbs, changes the migration process of heavy metals in the natural environment, and thus alleviates the current situation of heavy metal pollution.

Preparation, characterization and adsorption characteristics of diatom-based Cd(II) surface ion-imprinted polymer

Lili Huang,Lanqing Wang,Liang Gong,Qinglin Xie,Nanchun Chen

Cd(II)-based metal–organic framework-derived CdS photocatalysts for enhancement of photocatalytic activity

Ma Ligang,Ai Xiaoqian,Yang Xingming,Cao Xiaoxiao,Han Dianrong,Song Xiang,Jiang Huilin,Yang Wei,Yan Senlin,Wu Xiaoshan

CdS with band gaps of 2.4 eV is an essential semiconductor for optoelectronic and photocatalytic devices. In this study, Cd(II)-based metal–organic framework (MOF)-derived CdS photocatalysts are successfully synthesized using a facile chemical bath deposition method. CdS precursors are derived from Cd-based MOFs that H 2 S gas was bubbled into as S source. Four kinds of CdS nano-photocatalyst are obtained through controlling the thermal annealing process of CdS precursors. The excellent photocatalytic performance of CdS and the benefits of the porous and molecular sieving properties of MOFs are well integrated. The evolution of the morphology, microstructure, and optical properties are investigated by various characterization methods. The results indicate that the sample with an annealing temperature of 500 °C is primarily nanosheet structures with sizes ranging from 20 to 30 nm, which construct a porous network structure, Moreover, the best photodegradation activity is obtained by illuminating the catalyst in rhodamine-B dye solution for 80 min and reducing the absorption intensity to nearly zero. Finally, the pollutant degradation mechanism was analyzed in detail.

Bamboo-derived porous bioadsorbents and their adsorption of Cd(II) from mixed aqueous solutions

Xiao-kun OuYang,Ru-Na Jin,Le-Ping Yang,Yang-Guang Wang,Li-Ye Yang

Two porous bioadsorbents were successfully prepared from the partial enzymatic hydrolysis of bamboo and subsequent chemical modification with succinic anhydride. We investigated the abilities of the partially enzymatically hydrolyzed bamboo (PEB) and the porous succinylated bamboo (PSB) to adsorb Cd(II) from a solution containing sodium chloride and an amino acid. The partial enzymatic hydrolysis created many pores within the raw bamboo, and both the porous structure and the post-succinylation carboxyl group content were important for high adsorption capacity. The presence of sodium chloride and the amino acid markedly decreased the adsorption capacities of the bioadsorbents. The experimental data could be described perfectly with the Langmuir adsorption isotherm model and pseudo second-order kinetics model. Even in solutions containing sodium chloride and arginine, the maximum Cd(II) adsorption capacities at 303 K were 38.18 and 120.34 mg g−1 for PEB and PSB, respectively.

Efficient removal of Cd (II) from aqueous solution by chitosan modified kiwi branch biochar

Yuehui Tan,Xirui Wan,Xue Ni,Le Wang,Ting Zhou,Huimin Sun,Nong Wang,Xianqiang Yin

Production of cost-efficient composite materials from low-cost modified biochar for the removal of Cd (II) from wastewater is much needed to meet the growing needs of industrial wastewater treatments . A novel chitosan-modified kiwi branch biochar (CHKB) was fabricated as low-cost modified biochar for the removal of Cd (II) from aqueous solution. Batch adsorption and characterization experiments indicated that the modification of kiwi biochar (KB) by chitosan remarkably improved its adsorption performance. The results revealed that the adsorption isotherms can be best described by a Langmuir model and that a pseudo-second-order model fits the Cd (II) adsorption kinetics well, which indicates that it is a monolayer process controlled by chemisorption . CHKB exhibited a Langmuir maximum adsorption capacity of Cd (II) (126.58 mg g −1 ), whereas that of KB was only 4.26 mg g −1 . The adsorption ability of CHKB was improved by increasing the surface area and an abundance of surface functional groups (-OH, –NH, C O, etc.). The cation exchange, electrostatic interaction, surface complexation, and precipitation were the main mechanisms in the sorption of Cd (II) on CHKB. Excellent adsorption performance, low cost, and environmental-friendliness made CHKB a fantastic adsorbent for the removal of Cd (II) in wastewater.

Boosted capture of trace Cd(II) with a magnetic dual metal-organic-framework adsorbent

Jiehong Chen,Yan Li,Gangfeng Liang,Na Ma,Wei Dai

The microcrystalline powders of metal-organic frameworks (MOFs) are usually difficult to be separated and reused, restricting their applications for cadmium ions (Cd(II)) removal from water. Thus, it is imperative to develop the magnetic adsorbents with high adsorption performances and excellent recoverability. Herein, a novel type of magnetic dual MOFs composite for Cd(II) capture has been successfully synthesized with (ZIF-67)-on-(PMA@MIL-125-NH 2 ) as the adsorption mainstay and Fe 3 O 4 nanoparticle as the magnetic component. The advantages of the combination and its synergistic effect are achieved through the self-assembly process. Owing to the associate effect of abundant adsorption sites and high porosity, (ZIF-67)-on-(PMA@MIL-125-NH 2 @Fe 3 O 4 ) exhibits a significant adsorption capacity (152 ​mg ​g −1 ) and rapid adsorption rate (20 ​min) towards Cd(II). The adsorption data are well fitted by the Freundlich and pseudo-second-order kinetic models. The adsorption mechanism involves the critical contributions of π-π interaction, Lewis's acid-base, surface adsorption, electrostatic attraction, etc. Moreover, the adsorbent could be easy obtained from liquid through Fe 3 O 4 magnetism , exhibiting a good reusability. This work provides a new perspective on the synthesis of high-efficiency adsorbents for the Cd(II) capture from water.

RETRACTED: Two new luminescent Cd(II) coordination polymers and their application values on children bronchopneumonia

Hong-Xia Song,Ting Lei,Fang Wu,Xiaoyu He,Jiang Wang

This article has been retracted: please see Elsevier Policy on Article Withdrawal ( http://www.elsevier.com/locate/withdrawalpolicy ). This article has been retracted at the request of the Editor-in-Chief. In investigating concerns brought up regarding the authenticity of the article, the editors reached out to the corresponding author for an explanation. The authors failed to reply. The editors therefore feel that the findings of the manuscript cannot be relied upon and that the article needs to be retracted.

Crosslinked Electro-Spun Chitosan Nanofiber Mats with Cd(II) as Template Ions for Adsorption Applications

Li Yan,Xu Cong,Qiu Tianbao,Xu Xiaoyan

The Cd(II) ion imprinting electro-spun crosslinked chitosan nanofiber mats were successfully prepared using Cd(II) as template ions and glutaraldehyde (GA) as crosslinker to investigate the adsorption of Cd(II) and Pb(II) ions in aqueous solutions. The Cd(II) ion imprinting electro-spun crosslinked chitosan nanofiber mats were characterized by the Fourier Transform Infrared Spectrometer (FTIR), Scanning Electron Microscope (SEM), Thermal Gravimetric Analysis (TGA), elemental analysis and solubility tests. The prepared chitosan nanofiber mats exhibited a higher adsorption capacity for both Cd(II) (364.3 mg/g) and Pb(II) (272.0 mg/g) ions. The dynamic study demonstrated that the adsorption process followed the second-order kinetic equation. Langmuir and Freundlich adsorption models were used to analyze the equilibrium isotherm data. The results showed that the Langmuir model was best suitable for predicting the adsorption isotherm of the studied system. The as prepared Cd(II) ion imprinting electro-spun crosslinked chitosan nanofiber mats might be used as an effective adsorbent for Cd(II) and Pb(II) removal from heavy metal wastewater.

Electrochemical Sensor Based on Porous Biochar-Loaded MnO2 Nanocomposite for Sensitive Detection of Cd(II)

Baoli Wang,Kai Tang,Feng Yang

Understanding the extent of cadmium (Cd) contamination and its impact on the food industry and ecosystems is crucial; to this end, electrochemical methods provide sensitive and rapid responses for the in situ detection of heavy metal ions. In this paper, a sensitive Cd2+electrochemical sensor was constructed by using a composite material composed of biomass-derived porous carbon and manganese dioxide (MnO2/KLSC). The composite was demonstrated to have a porous structure with quasi-cubic MnO2particles evenly distributed on the carbon matrix. Using MnO2/KLSC as the electrode material, a simple electrochemical sensing platform was fabricated for the detection of Cd2+. The electrochemical analysis showed that the Cd2+sensor has good performance, with a linear detection range of 0.01–80.0 μmol/L and a detection limit of 9.8 nmol/L. Furthermore, the sensor shows excellent repeatability, reproducibility, and good anti-interference. The sensor was successfully applied to analyze rice and sea water samples, demonstrating satisfactory recovery rates. The good performance of MnO2/KLSC/GCE can be attributed to the excellent electrical conductivity, enlarged active surface area, and good electron transfer capability.

Temperature-controlled Structural Diversity of Two Cd(II) Coordination Polymers Based on the Dicarboxylate Ligand①

Fang-Min CHEN,Chi-Chi ZHOU,Xiong HE,Yan LI,Xiu-Qing ZHANG

ABSTRACT Two new 3-D Cd(II) coordination polymers with p -phthalic acid ( p -BDC) and 4,4΄-dipyridylamine (4,4΄-dpa), namely [Cd 2 ( p -BDC) 2 (4,4΄-dpa) 2 ] n 1 and {[Cd( p -BDC)(4,4΄-dpa) (H 2 O)]·4H 2 O} n 2 were successfully synthesized under hydrothermal conditions at 120 and 140 °C. They were characterized by single-crystal X-ray diffraction, IR, PXRD and TGA . It was further characterized by Hirshfeld surface (HS) analysis for complex 2 . The luminescent properties of the complexes have also been investigated.

Byproducts of the anammox-hydroxyapatite coupling process — Characterization and its adsorption capacity for Cd(II)

Ying Wang,Haoyu Chen,Chao Chen,Zikun Zhang,Yin Xu,Guangjiao Chen,Yanlong Zhang

The anammox-HAP coupling process can simultaneously achieve high-efficiency nitrogen removal and phosphorus recovery from sewage. The composition and physical properties of the byproducts (aHAP) collected in the anammox-HAP process were analyzed. In addition, the application potential and mechanisms for Cd(II) adsorption by aHAP in wastewater were investigated. The results show that aHAP is mainly composed of hydroxyapatite and calcium carbonate , having granular structure with honeycombs and pores. The aHAP shows an adsorption capacity of 21.10–34.80 mg/g for Cd(II) removal, and the adsorption behavior is consistent with pseudo-second-order and intra-particle diffusion models, showing that the rate-limiting step is controlled by the chemical reaction of surface complexation, ion exchange, and precipitation. In addition, the remaining anammox biomass in aHAP can bind Cd(II). The aHAP also shows a pH buffer capacity when the initial pH ranges between 4.10 and 8.46, and the final pH can be stabilized in the range of 6.3 to 8.3, which is suitable for anammox reactions. Collectively, the anammox-HAP coupling process can not only be used to achieve high-efficiency nitrogen and phosphorus removal, but its aHAP byproduct shows good adsorption properties and pH buffering capacity, which meets the requirements of green chemistry and has high economic and environmental benefits.