查找使用阿拉丁产品的科研文献

The design and preparation of NDI modified MOFs for high efficiency removal of MB and Cr(VI)

Zewan Qin,Qing Guan,Yating Lu,Yu Tian,Xia Yang

The naphthalene tetracarboxdiimide (NDI) modified NH 2 -UiO-66(Zr) and NH 2 -MIL-101(Cr) (NDI/UZr and NDI/MCr for short) metal organic frameworks (MOFs) materials with strong covalent bond O C–N–C O were designed and prepared by solvothermal method. The comprehensive physical and chemical properties of the materials were characterized, and the adsorption and photocatalytic properties of the materials were evaluated by using methylene blue (MB) and Cr(VI) in single and mixture system. When the initial concentration of MB was 50 mg·L −1 , the photocatalytic degradation rate constant of NDI/MCr(2:1) was 10.3 and 13.8 times higher than that of NH 2 -MIL-101(Cr) and NDI/UZr(2:1), respectively. Additionally, NDI/MCr(2:1) exhibited 1.6 times higher reaction rate constant than that of NDI/UZr(2:1) for the removal of 10 mg∙L −1 Cr(VI). The enhanced adsorption and photocatalytic ability over NDI/MOFs were attributed to the MOFs larger specific surface area and wider spectral response, and NDI showed high electron affinity, superior charge carrier transport properties. Free radical and electron capture experiments indicated that h + , •O 2 − , and e − were the main active species in the NDI/MOFs system. Among them h + and •O 2 − played an essential role in the removal of MB, while e − and •O 2 − contributed to the photocatalytic reduction of Cr(VI). The mechanism of the photocatalytic process was discussed in detail.

Discovery of Novel N-[(dimethylamino)methylene]thiourea (TUFA)-Functionalized Lignin for Efficient Cr(VI) Removal from Wastewater

Haixin Wang,Tao Shen,Yiming Wang,Zongxiang Lv,Yu Liu,Juan Wu,Tai Li,Shui Wang,Yanguo Shang

This study developed a novel adsorbent for Cr (VI) removal from wastewater by grafting N-[(dimethylamino)methylene]thiourea (TUFA) onto lignin. The resulting TUFA-functionalized lignin adsorbent AL was comprehensively characterized using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), nuclear magnetic resonance (NMR), and X-ray photoelectron spectroscopy (XPS). Batch adsorption experiments systematically evaluated the influence of solution pH, contact time, temperature, initial Cr (VI) concentration, and adsorbent dosage. AL exhibited high adsorption capacity (593.9 mg g−1at 40 °C), attributed to its abundant nitrogen and sulfur-containing functional groups. Kinetic analysis revealed that the adsorption process followed pseudo-second-order kinetics. Equilibrium isotherm data were best described by the Langmuir model, indicating predominant monolayer chemisorption. Thermodynamic parameters demonstrated that Cr (VI) adsorption onto AL is spontaneous, endothermic, and entropy-driven. The adsorption mechanism involves membrane diffusion and intra-particle diffusion processes. This work successfully synthesized a stable, effective, and low-cost adsorbent (AL) using an amine agent incorporating both nitrogen and sulfur functional groups, offering a promising approach for treating Cr (VI)-contaminated wastewater.

Rationally engineered core-shell structured Fe0@FeS towards the efficacious synergistic Cr(VI) and Ni(II) removal

Zishen Lin,Chunli Zheng,Zhenxing Wang,Yuanzhe Peng,Guoqing Geng,Aibin Zhu,Chi He

As one category of promising and efficacious purification material toward environmentally harmful heavy metals, sulfidated amorphous zero-valent Iron (S@AZVI) exhibits unparalleled removal performance. Due to the disruptive crystal growth however, the irreversible loss of Fe 0 component during conventional synthesis route poses a substantial hindrance to its industrial application. To address this, we propose a post-sulfidation strategy to hinder the transformation of Fe 0 by altering the shell composition of AZVI from Fe 2 O 3 to FeS, which maintains a remarkable Fe 0 content up to 75.7 % over finally obtained S@AZVI, far higher than the material obtained through the one-step sulfidation . Attributing to the synergy of FeS shell and substantial Fe 0 , S@AZVI demonstrates impressive performance as the lowest free corrosion potential (−1.050 V) and work function (4.058 eV), and subsequently exhibits a notable enhancement in the removal efficiency of Cr(VI) and Ni(II), surpassing AZVI by 1.8 and 2.0 times, respectively. Results reveal that the adsorption, reduction, and coprecipitation constitute the mechanisms governing the removal of Cr(VI) and Ni(II). In practical electroplating wastewater experiments, S@AZVI effectively removes Cr(VI) and Ni(II) within a 60-min timeframe, meeting established emission standards. These findings provide valuable insights for future AZVI material synthesis for heavy metal elimination.

Removal of hypertoxic Cr(VI) from water by polyaniline-coated ZIF-67-derived nitrogen-doped magnetic carbon

Wang Changlong,Sun Qian,Yang Qing,Wei Huiying,Yang Yanzhao

Heavy metals are highly toxic and nonbiodegradable, posing a serious threat to the water environment and human beings. Therefore, it is crucial to develop a highly efficient adsorbent that is easy to recover and separate for the removal of heavy metals. In this paper, nitrogen-doped magnetic carbon (NC-67) was prepared by carbonization and hydrochloric acid treatment using cobalt-containing MOF (ZIF-67) as precursor. Then, polyaniline (PANI) was grown directly on NC-67 with high specific surface area by in situ polymerization to prepare polyaniline-coated nitrogen-doped magnetic carbon (NC-67@PANI), which was characterized by XRD, SEM, TEM and VSM, etc. and used for the removal of Cr(VI)from wastewater. The experimental results showed that the adsorption process of Cr(VI) by NC-67@PANI was spontaneous and endothermic, which conformed to the pseudo-second-order model and Freundlich adsorption isotherm model. Due to the synergistic effect of adsorption and reduction, the experimental adsorption capacity of NC-67@PANI for Cr(VI) was 410.2 mg/g. NC-67@PANI maintained a removal efficiency of 65.8% for Cr(VI) after five cycles. In addition, NC-67@PANI had good magnetism and was easy to separate under external magnetic field. The excellent adsorption capacity and easy separation characteristics of NC-67@PANI indicate that it is a promising adsorbent for Cr(VI) removal from wastewater. Graphical Abstract

Fluorescent Sensors Based on Organic Polymer-Capped Gold Nanoparticles for the Detection of Cr(VI) in Water

Na Wang,Liangchen Wang,Hong Yang,Tingting Xiong,Shangping Xiao,Jiawen Zhao,Weiping Du

“Turn-off” fluorescent sensors for Cr(VI) have been fabricated based on organic polymer-capped gold nanoparticles. The fluorescence intensity, as well as the response behavior of the sensors, is dependent on the pH values of buffer solution and dilution amounts of the sensors. When diluted 50 times with pH 2.0 buffer solution, the sensors show good linear responses toward Cr(VI) at concentrations between 2.8–5.9 μM and 5.9–29 μM. The calculated detection limit is 0.63 μM (S/N=3). The interference study and real sample assays exhibit satisfying selectivity and reliability results. Furthermore, the quenched intensity of fluorescence could be recovered by Fe(II) ion, which provides a potential method to detect Fe(II) ions. The quenching and recovering mechanisms have also been investigated. It is suggested that the quenching mechanism is based on the combined effects of internal electron transfer and the inner filter effect. Finally, the recovering mechanism is based on the redox reactions between the Cr(VI) and Fe(II) ions.

Selective adsorption and separation of Cr(VI) by surface-imprinted microsphere based on thiosemicarbazide-functionalized sodium alginate

Yapei Luo,Heng Li,Minghua Wu,Wei Wang,Lili Wang

One-Step Synthesis of Visible-Responsive Diatomite/g-C3N4 Composite and its Catalytic Degradation for Cr(VI)

Yu Quan Ren,Shi Yong Sun,Edward Opong Acheampong,Fa Qin Dong,Biao Biao Ma,Ke Wang,Xiao Yu Fan

A one-step synthesis of visible light responsive diatomite/g-C3N4 composite material was prepared by impregnation-calcination method. The products were characterized by Scanning electron microscope, X-ray diffractometer, Ultraviolet diffuse reflectance spectroscopy, Fourier transform infrared spectrometer, and Photoluminescence spectrometer. The SEM results showed that g-C3N4 was successfully attached onto the surface of the diatomite. Also the composite materials were more light-responsive compared with the single phase material. The composite materials had a maximum degradation efficiency up to nearly 91.79%. The significant improvement in photocatalytic performance was due to the porous structure of diatomite, increase of contact area of carbon nitride.

Synthesis and evaluation of ion-imprinted composite membranes of Cr(VI) based on β-diketone functional monomers

Peng Li,Xin Wang,Guifang Wang,Li Zhao,Yuwen Hong,Xianzhi Hu,Futing Zi,Huiling Cheng

Using Cr(VI) as the imprinted ions and 2-allyl-1,3-diphenyl-1,3-propanedione (ADPD) (a compound synthesized by independent design) as the functional monomer, a series of chromium ion-imprinted composite membranes (Cr(VI)-IICMs) and corresponding non-imprinted composite membranes (NICMs) were synthesized and tested. The results showed that the Cr(VI)-IICM10 membrane prepared under optimal experimental conditions exhibited a high adsorption capacity towards Cr(VI) (Q = 30.35 mg g−1) and a high imprinting factor (α = 2.70). The structural characteristics of Cr(VI)-IICM10 and NICM10 were investigated using FE-SEM, ATR-FTIR, and BET techniques combined with UV-Vis photometry and inductively coupled plasma emission spectrometry (ICP-OES) to evaluate the adsorption performance and permeation selectivity, while the effect on adsorption permeance of varying the experimental conditions including the solvent type, pH, and temperature was also investigated. The results showed that Cr(VI)-IICM10 is a mesoporous material with excellent permeation selectivity, reusability, and favorable pH response, and that its adsorption behavior is in accordance with the Langmuir model and pseudo-first-order kinetics. Thus, Cr(VI)-IICM10 shows great potential towards utilization as a “smart membrane” to control the separation and removal of Cr(VI) in wastewater, and also proved a reasonable design of the new functional monomer ADPD.

Construction of the Bi2WO6/Bi4V2O11 heterojunction for highly efficient visible-light-driven photocatalytic reduction of Cr(VI)

Chol-Nam Ri,Kim Song-Gol,Jong Ju-Yong,Sung-Nam Pak,Song-Chon Ri,Jong-Hwa Ri

Herein, a Bi2WO6/Bi4V2O11 heterostructured photocatalyst was fabricated through a facile one-pot solvothermal method. In this heterojunction system, highly homogeneous-dispersed Bi4V2O11 nanocrystals were anchored onto Bi2WO6 nanoflakes, endowing the heterojunction with nanosized interfacial contact. Because of the favorable interfacial contact and band alignment, photoinduced charge carrier transfer is facilitated in the Bi2WO6/Bi4V2O11 heterojunction, which can be verified by photocurrent and photoluminescence measurements. In contrast with pristine Bi2WO6 and Bi4V2O11 samples, the Bi2WO6/Bi4V2O11 heterostructured photocatalyst displays drastically improved photocatalytic Cr(VI) reduction activity under visible-light irradiation. More significantly, the as-fabricated heterojunction possesses superior activity for Cr(VI) relative to the counterpart obtained by mechanical mixing, indicating that the interfacial contact plays a determinant role in promoting charge carrier transfer. Moreover, Bi2WO6/Bi4V2O11 heterojunctions exhibited good cycling stability even after 5 cycles. A plausible photocatalytic Cr(VI) reduction reaction mechanism over the Bi2WO6/Bi4V2O11 heterojunction is proposed on the basis of band alignment. This work reports a high-efficiency photocatalyst for Cr(VI) and might shed light on the decisive factor for optimizing the heterostructure.

Magnetically Separable MoS2/Fe3O4/nZVI Nanocomposites for the Treatment of Wastewater Containing Cr(VI) and 4-Chlorophenol

Haijiao Lu,Jingkang Wang,Hongxun Hao,Ting Wang

With a large specific surface area, high reactivity, and excellent adsorption properties, nano zerovalent iron (nZVI) can degrade a wide variety of contaminants in wastewater. However, aggregation, oxidation, and separation issues greatly impede its wide application. In this study, MoS2/Fe3O4/nZVI nanocomposites were successfully synthesized by a facile step-by-step approach to overcome these problems. MoS2nanosheets (MNs) acted as an efficient support for nZVI and enriched the organic pollutants nearby, leading to an enhanced removal efficiency. Fe3O4nanoparticles (NPs) could not only suppress the agglomeration and restacking of MNs, but also facilitate easy separation and recovery of the nanocomposites. The synergistic effect between MNs and Fe3O4NPs effectively enhanced the reactivity and efficiency of nZVI. In the system, Cr(VI) was reduced to Cr(III) by nZVI in the nanocomposites, and Fe2+produced in the process was combined with H2O2to further remove 4-Chlorophenol (4-CP) through a Fenton reaction. Furthermore, the nanocomposites could be easily separated from wastewater by a magnet and be reused for at least five consecutive runs, revealing good reusability. The results demonstrate that the novel nanocomposites are highly efficient and promising for the simultaneous removal of Cr(VI) and 4-CP in wastewater.Keywords:nZVI;modification;nanocomposites;Cr(VI);4-CP;Fenton reaction;pollution treatment;recyclability;wastewater

A novel two-dimensional accordion-like titanium carbide (MXene) for adsorption of Cr(VI) from aqueous solution

Yi Tang,Chenhui Yang,Wenxiu Que

Herein, we report on a novel two-dimensional (2D) material application, which shows that an accordion-like layered Ti 3 C 2 nanomaterial (MXene) with an excellent adsorption capacity of Cr(VI) from aqueous solution was prepared by etching Al layer from Ti 3 AlC 2 phase in hydrofluoric acid (HF) solution. Ti 3 C 2 nanopowders were well characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and the physical property of as-obtained samples was studied by UV–Vis diffuse reflectance spectra (DRS). After HF treatment, Ti 3 AlC 2 not only has a phase transition from one crystal to another, but surprisingly, its microstructure is also undergoing an obvious change. Ti 3 C 2 with product of change possesses an accordion-like multilayer structure, and a relatively higher specific surface area (SSA) than untreated Ti 3 AlC 2 . Then, accordion-like Ti 3 C 2 with a high SSA provides abundant active sites for pollutant removal and functionalization. Accordion-like Ti 3 C 2 nanomaterial exhibits a stable adsorption capacity, and 1 g as-prepared accordion-like Ti 3 C 2 powders can remove about 80 mg potassium dichromate. Therefore, the results suggest that 2D MXenes are promising as an effective nanoadsorbent in heavy metal removal from the wastewater.

Triethanolamine interface modification of crystallized ZnO nanospheres enabling fast photocatalytic hazard-free treatment of Cr(vi) ions

Xiaowen Su,Zehua Wang,Yuan Huang,Zhenyu Miao,Shuhua Wang,Jianjun Wang,Xiao Li Zhang,Xiaomin Sun,Hong Liu,Yuanhua Sang

The hazard-free treatment of Cr( vi ) ions is critical in modern industry. Photocatalytic reduction and detoxification are high-potential strategies. Photocatalysts with high efficiency, low cost, environmental friendliness, and easy mass products are required. In this study, we report a facile strategy using triethanolamine (TEOA) as a capping ligand to modify the surface of ZnO nanospheres. The experimental and theoretical results reveal that the presence of TEOA on the surface was beneficial for electron enrichment on Zn and hole transfer to TEOA and can photocatalytically reduce Cr( vi ) by almost 100% in 5 min. The photocatalytic property of TEOA-modified ZnO could be renewed by the reabsorption of TEOA in solution. The great sedimental properties benefit photocatalyst recycling and renewal, which also provides high potential for water pollution and environmental emergency responses applications.