查找使用阿拉丁产品的科研文献

Ultra-high capacity and anti-interference for Cr(VI) removal by tannin-polyvinylimine modified graphite carbon nitride

Wen Sun,Rui Wang,Lingfei Li,Jun Zhao,Bianhua Liu

To combat the increasingly serious water pollution caused by heavy metal ions , the development of efficient adsorbents is of great significance. In this study, a novel composite adsorbent for Cr(VI) removal was smartly designed using environmentally friendly materials such as tannic acid (TA) and polyethyleneimine (PEI) for surface modification of g-C 3 N 4 nanosheets through covalent assembly of polyphenols and amines. The obtained (PEI-TA)-g-C 3 N 4 composite was capable of efficiently and quickly adsorbing Cr(VI) in water, with a maximum adsorption capacity of 769.23 mg/g at 308 K (35 °C), which was much higher than most reported Cr(VI) adsorbents. Notably, (PEI-TA)-g-C 3 N 4 could reduce highly toxic Cr(VI) to low toxic Cr(III) and effectively adsorb it. The Cr(VI) adsorption process was a spontaneous thermal adsorption process that conformed to the pseudo-second-order kinetic model and Langmuir isotherm model. In addition, the excellent photothermal performance of (PEI-TA)-g-C 3 N 4 further accelerated the adsorption of Cr(VI). Moreover, the strong anti-interference ability of (PEI-TA)-g-C 3 N 4 composite against anions and other metal ions enabled it to effectively remove Cr(VI) in complex environments, expanding its practical application scenarios. The polymer coatings rich in phenolic hydroxyl- and amine-rich formed on the large surface area of g-C 3 N 4 and the protonation of the amino groups are the keys for (PEI-TA)-g-C 3 N 4 composite to have ultra-high adsorption performance and strong anti-interference ability towards Cr(VI). The designed strategy of this metal-free and environmentally friendly composite with ultra-high removal of Cr(VI) capability from wastewater provides new ideas for developing green, inexpensive, and efficient adsorbents.

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.

The influence of Mn(II) on transformation of Cr-absorbed Schwertmannite: Mineral phase transition and elemental fate

Hongmei Tang,Meiqing Chen,Pingxiao Wu,Yihao Li,Tianming Wang,Jiayan Wu,Leiye Sun,Zhongbo Shang

Schwertmannite (Sch) is considered as an effective remover of Chromium (Cr) due to its strong affinity for toxic Cr species. Since the instability of Sch, the environmental fate of Cr deserves attention during the transformation of Sch into a more stable crystalline phase. The ubiquitous manganese(II) (Mn(II)) probably affects the transformation of Sch and thus the environmental fate of Cr. Therefore, this study investigated the impact of Mn(II) on the transformation of Cr-absorbed Sch (Cr-Sch) and the associated behavior of SO 4 2− and Cr. We revealed that the transformation products of Cr-Sch at pH 3.0 and 7.0 were goethite and Sch, respectively. The presence of Mn(II) weakened the crystallinity of the transformation products, and the trend was positively correlated with the concentration of Mn(II). However, Mn(II) changed the transformation products of Cr-Sch from hematite to goethite at pH 10.0. Mn(II) replaced Fe(III) in the mineral structures or formed Mn-O complexes with surface hydroxyl groups (-OH), thereby affecting the transformation pathways of Sch. The presence of Mn(II) enhanced the immobilization of Cr on minerals at pH 3.0 and 7.0. Sch is likely to provide an channel for electron transfer between Mn(II) and Cr(VI), which promotes the reduction of Cr(VI). Meanwhile, Mn(Ⅱ) induced more -OH production on the surface of secondary minerals, which played an important role in increasing the Cr fixation. In addition, part of the Mn(Ⅱ) was oxidized to Mn(Ⅲ)/Mn(Ⅳ) at pH 3.0 and pH 7.0. This study helps to predict the role of Mn(II) in the transformations of Cr-Sch in environments and design remediation strategies for Cr contamination.

Spanning green to deep red emission: KAl₁₁O₁₇: Cr³⁺ phosphors engineer light spectra for enhanced plant growth

Ming Ma,Jiale Zhang,Wenjun Zhang,Ying Gao,Dan Wang,Zihan Chen

Plants have a limited ability to absorb green light. Additionally, the energy distribution of sunlight in the deep-red region is weak. These factors restrict the efficiency of plant growth and limit yield improvements. In this study, a novel deep-red phosphor material, KAl₁₁O₁₇: Cr³⁺, was designed and synthesized through a high-temperature solid-state method. This material exhibits deep-red light emission at a central wavelength of 697   nm under broadband excitation at 430   nm (near-ultraviolet) and 562   nm (green light). By leveraging a "light-cutting" mechanism, the phosphor converts underutilized green light into far-red light, which strongly aligns with the absorption peak of the plant photoreceptor P FR state. When applied as a thin-film coating, the material significantly enhances lettuce growth under controlled green-light irradiation. These findings demonstrate the potential of KAl₁₁O₁₇: Cr³⁺ in optimizing spectral distribution for energy-efficient agricultural lighting systems.

Cr substitution enhances Zr0.95V0.05Co1-xCrx(x = 0–0.15) alloy’s hydrogen isotope storage and anti hydrogen-induce disproportionation

Lu Wen,Chaojie Li,Houqun Xiao,Huazhou Hu,Ruizhu Tang,Chengsi Hu,Chuanming Ma,Chaobin Lai,Luocai Yi,Qingjun Chen

The ZrCo alloy, considered an ideal candidate material for hydrogen (or its isotope) storage to replace uranium in the ITER, faces challenges due to its susceptibility to hydrogen-induced disproportionation, which leads to a diminished cycling life. To address this, we investigated the substitution of V and Cr for Zr and Co. Our study reveals that this substitution not only refines the grain size and expands the lattice constant but also significantly enhances the kinetics of hydrogen absorption. Notably, the Zr 0.95 V 0.05 Co 0.85 Cr 0.15 alloy demonstrates a remarkable 98.8 % reduction in the time required to absorb 90 % of its full capacity compared to ZrCo. This alloy also exhibits superior isotope effects under H 2 and D 2 environments, along with lower enthalpy and entropy for dehydrogenation, contributing to a reduced dehydrogenation temperature and enhanced resistance to disproportionation. After 50 cycles of hydrogen absorption and desorption, the hydrogen storage capacity of Zr 0.95 V 0.05 Co 0.85 Cr 0.15 alloys decreases by only 5.7 %, significantly outperforming other reference samples and demonstrating its exceptional anti-disproportionation capability. These results indicate that the Zr 0.95 V 0.05 Co 0.85 Cr 0.15 alloy exhibits the best resistance to hydrogen-induced disproportionation. Moreover, post-50 cycling analysis confirms that the phase of the alloy is still dominated by the ZrCo phase, indicating its excellent structural stability. Our findings offer valuable insights into optimizing ZrCo-based alloys for enhanced hydrogen storage performance and cycling stability, providing potential references for advancements in hydrogen isotope storage materials design.

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

Preparation of unsaturated MIL-101(Cr) with Lewis acid sites for the extraordinary adsorption of anionic dyes

Keshta Basem E.,Yu Haojie,Wang Li,Yi Hong,Jian Shan,Uddin MD Alim,Ouyang Chenguang,Wang Yu,Yuan Xunchun,Zhang Yanhui,Jin Yang,Basit Abdul,Owais Malik Muhammad,Awan Khan Manqoosh

Anionic dyes contaminate water and severely disrupt aquatic ecosystems, urgently demanding effective treatment solutions for safety. This study explores the synthesis of unsaturated MIL-101(Cr) and its exceptional performance in removing anionic dyes from polluted water systems. The synthesized MIL-101(Cr) exhibits medium Lewis’s acid and strong Brønsted acid sites, a high specific surface area (>3000 m 2 /g), and a Zeta potential of 30 mV, contributing to its strong adsorption capability. Adsorption studies reveal Langmuir isotherm model fitting, with maximum adsorption capacities of 4231, 1266, and 568 mg/g for Acid Blue 92, Congo Red, and Acid Blue 90, respectively. The chemisorption process follows pseudo-second-order kinetics and is spontaneous and exothermic. MIL-101(Cr) demonstrates chemical and water stability, maintaining over 80% removal efficiency after five recycling cycles. This research provides valuable insights into treating anionic dye-contaminated wastewater using MIL-101(Cr) as an efficient adsorbent.

Simultaneous measurement of Cr(III) and Cu(II) based on indicator-displacement assay using a colorimetric nanoprobe

Xianfeng Wang,Chengxiang Chu,Jiayi Lv,Yuanyuan Jia,Libo Lin,Mei Yang,Suyi Zhang,Danqun Huo,Changjun Hou

High-performance analysis of heavy metal ions is great importance in both environment and food safety. In this work, a facile and reliable colorimetric sensor was presented for simultaneous detection of Cu 2+ and Cr 3+ based on indicator-displacement assay (IDA). As a typical silicate nanomaterials , ZnSiO 3 hollow nanosphere (ZSHS) exhibited an outstanding ion exchange capacity. Zincon was incorporated with the ZSHS to form a zincon/ZSHS hybrid ionophore with a blue color. Upon the addition of Cr 3+ , IDA reaction and selective ion exchange occurred with the color change of zincon/ZSHS ionophore from blue to yellow. With such a design, colorimetric measurement of Cr 3+ was realized. The linear concentration for Cr 3+ detection ranged from 0.5 μM to 75 μM with the LOD of 83.2 nM. Furthermore, we also screened different kinds of complexing agents that may respond with zincon/ZSHS ionophore and various metal ions. It was found that tartaric acid (TA) showed the chelation capability of Zn 2+ -TA is stronger than that of Zn 2+ -zincon. Thus zincon/ZSHS/TA presented a yellow color due to the chelation reaction of Zn 2+ -TA, releasing the zincon as a free state. After addition of Cu 2+ , a stronger chelation reaction of Cu 2+ -zincon occurred. This process involved in the color change from yellow to blue and realized colorimetric measurement of Cu 2+ . The detection limit of Cu 2+ was calculated to be 43.7 nM with linear range from 0.1 to 20 μM. In addition, the zincon/ZSHS nanoprobe was successfully applied for simultaneous measurement of Cu 2+ and Cr 3+ in sorghum and river water, indicating that the zincon/ZSHS nanoprobe provided a promising sensing platform in environment and food safety.

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