查找使用阿拉丁产品的科研文献

Z-scheme heterojunction Zn3(OH)2(V2O7)(H2O)2/V-Zn(O,S) for enhanced visible-light photocatalytic N2 fixation via synergistic heterovalent vanadium states and oxygen vacancy defects

Pengkun Zhang,Qinhan Wu,Haoyu Wang,Dong-Hau Kuo,Yujie Lai,Dongfang Lu,Jiqing Li,Jinguo Lin,Zhanhui Yuan,Xiaoyun Chen

Herein, we established a Zn 3 (OH) 2 (V 2 O 7 )(H 2 O) 2 /V-Zn(O,S) Z-scheme heterojunction (labeled ZnVO/V-Zn(O,S) with a heterovalent V 4+ /V 5+ states and oxygen vacancies in both phases via a one-step in-situ hydrolysis method. The NaBH 4 regulated the ZnVO/V-Zn(O,S)-3 with rich Vo and suitable n (V 4+ )/ n (V 5+ ) ratio achieved an excellent photocatalytic nitrogen fixation activity of 301.7 μmol/(g·h) and apparent quantum efficiency of 1.148% at 420 nm without any sacrificial agent, which is 11 times than that of V-Zn(O,S). The Vo acts as the active site to trap and activate N 2 molecules and to trap and activate H 2 O to produce the H for N 2 molecules photocatalytic reduction. The rich Vo defects can also reduce the competitive adsorption of H 2 O and N 2 molecules on the surface active site of the catalyst. The heterovalent vanadium states act as the photogenerated electrons, quickly hopping between V 4+ and V 5+ to transfer for the photocatalytic N 2 reduction reaction. Additionally, the Z-scheme heterojunction effectively minimizes photogenerated carrier recombination. These synergistic effects collectively boost the photocatalytic nitrogen fixation activity. This study provides a practical method for designing Z-scheme heterojunctions for efficient photocatalytic N 2 fixation under mild conditions.

Iron(III)-(1,10-Phenanthroline) Complex Can Enhance Ferrate(VI) and Ferrate(V) Oxidation of Organic Contaminants via Mediating Electron Transfer

Binbin Shao,Jing Deng,Hongyu Dong,Shuchang Wang,Enchao Li,Xiaohong Guan

Recent research has primarily focused on the utilization of reductants as activators for Fe(VI) to generate high-valent iron species (Fe(IV)/Fe(V)) for the degradation of emerging organic contaminants (EOCs). However, a significant drawback of this approach arises from the reaction between reductants and ferrates, leading to a decrease in oxidation capacity. This study introduces a novel discovery that highlights the potential of the iron(III)-(1,10-phenanthroline) (Fe(III)-Phen) complex as an activator, effectively enhancing the degradation of EOCs by Fe(VI) and augmenting the overall oxidation capacity of Fe(VI). The degradation of EOCs in the Fe(VI)/Fe(III)-Phen system is facilitated through two mechanisms: a direct electron transfer (DET) process and electron shuttle action. The DET process involves the formation of a Phen-Fe(III)–Fe(VI)* complex, which exhibits a stronger oxidation ability than Fe(VI) alone and can accept electrons directly from EOCs. On the other hand, the electron shuttle process utilizes Fe(III)-Phen as a redox mediator to transfer electrons from EOCs to Fe(VI) through the Fe(IV)/Fe(III) or Fe(IV)/Fe(II)/Fe(III) cycle. Moreover, the Fe(III)-Phen complex can improve the utilization efficiency of Fe(V) by preventing its self-decay. This study’s findings may present a viable option for utilizing an effective catalyst to enhance the oxidation of EOCs by Fe(VI) and Fe(V).

Simultaneous removal of As(V) and Pb(II) using highly-efficient modified dehydrated biochar made from banana peel via hydrothermal synthesis

Varney Edwin Johnson,Qi Liao,Bob Wisdom Jallawide,Richmond Anaman,Charles Amanze,Peicheng Huang,Wei Cao,Chunlian Ding,Yan Shi

Efficient removal of arsenic (As) and lead (Pb) from industrial wastewater has long been a critical environmental issue due to their serious risk to human health. Therefore, in this work, a modified banana peel biochar (MBPB) was prepared by mixing calcium nitrate , diammonium hydrogen phosphate , sulfuric acid, ferric nitrate with dehydrated banana peel biochar as adsorbent for As(V) and Pb(II) removal in wastewater, and their absorption mechanism was investigated. SEM-EDS, TEM, FTIR , XRD , XPS , BET, kinetic, and isothermal characteristics of MBPB and pristine banana peel biochar (PBPB) were conducted. The behavior of both metal ions on MBPB and PBPB was well explained by the pseudo-second-order kinetic with Langmuir and Freundlich models. We found that the two biochar’s behaviors were mixture processes of monolayer and multilayer adsorption , achieving maximum capacities as determined by the Langmuir model of 39.5 mg g −1 (MBPB-As), 33.2 mg g −1 (MBPB-Pb), 30.8 mg g −1 (PBPB-Pb), and 23.5 mg g −1 (PBPB-As), with maximum efficiencies of 98.7% (MBPB-As) and 90.3% (MBPB-Pb) under optimum conditions. Thermodynamic tests showed that As(V) and Pb(II) removal on MBPB was a spontaneous and endothermic physisorption process. MBPB showed great reusability in As(V) and Pb(II) removal, with removal rates as high as 71.4% and 66.5% after five cycles, respectively. Selective adsorption of As(V) and Pb(II) was also investigated on MBPB, and the removal rate was still high in the mixture of heavy metals. These findings provide a feasible method for the environmental-benign utilization of banana peel as a low-priced adsorbent in wastewater treatment .

Fine regulation on hour-glass like spongy structure of polyphenylsulfone (PPSU)/sulfonated polysulfone (SPSf) microfiltration membranes via a vapor-liquid induced phase separation (V-LIPS) technique

Yi Yu,Qiu Han,Haibo Lin,Shaofeng Zhang,Qiu Yang,Fu Liu

The fine micro-structure regulation of polymeric membranes is crucial to the separation performances. Herein, we prepared a novel Polyphenylsulfone (PPSU)/sulfonated polysulfone (SPSf) microfiltration membrane with ‘hour-glass’ like spongy micropore-structure via vapor and liquid induced phase separation (V-LIPS) technique. A precritical casting solution was prepared by adding a certain amount of H 2 O using N, N -dimethylacetamide (DMAc) as the solvent and Polyvinyl Pyrrolidone (PVP) as the pore-forming agent. The effect of residence time in vapor on membrane structures is extensively evaluated. Results revealed that the resultant membranes evolved from finger-like to bicontinuous structure with extending the exposure time (>5s) in vapor. The pure water flux of the membrane with the vapor time (30s) under the pressure of 0.2 bar reached a high value of 3045.7 ± 42.7 L/(m 2 ∙h). Moreover, the obtained membrane M3 showed excellent separation properties for surfactant-stabilized n-hexane-in-water, isooctane-in-water and decamethylcyclopentasiloxane (D5)-in-water emulsions with rejection coefficient up to >99%, >99% and >98% and high rejection of 99.0% to SiO 2 nanoparticles . Therefore, PPSU/SPSf membrane with controlled ‘hour-glass’ like spongy micro-pore structure showed high permeability with high rejection coefficient for both inorganic nanoparticles and oily water.

Selective and efficient removal of As(V) and As(III) from water by resin-based hydrated iron oxide

Yiqun Liu,Zhihao Chen,Xiaoshuang Yin,Yun Chen,Ying Liu,Wenzhong Yang

Arsenic pollution in natural water is a worldwide problem. In this work, a resin-based hydrated iron oxide (D303-HFO) adsorbent was designed to remove arsenate (As(V)) and arsenite (As(III)) in the groundwater. The structure and morphology of the D303-HFO adsorbent were characterized by FTIR, XRD , SEM and TEM tests. The specific surface area, pore volume and pore size increased with the incorporation of HFO nanoparticles in the resin. In addition, the effects of pH and coexisting ions on the arsenic removal efficiency were investigated. Results indicated that the D303-HFO had efficient removal performance for arsenic in the pH range of 3–9 and showed high selectivity for As(V) and As(III) under the influence of competitive ions. The adsorption kinetics study confirmed that the adsorption process was dominated by chemisorption , and the adsorption isotherms of As(V) and As(III) by D303-HFO fitted the Langmuir model. Thermodynamic parameters indicated that the adsorption reaction was spontaneous and exothermic. Moreover, the regeneration and stability experiment indicated that the D303-HFO adsorbent was super reusable after five consecutive cycles and could be put into service stably and permanently. The fixed-bed column test showed that the water sample containing As(V) and As(III) was treated with a volume of 900BV and 1100BV, respectively. After the treatment, the effluent concentration reached the drinking water standard stipulated by WHO.

Interfacial and build-in electric fields rooting in gradient polyelectrolyte hydrogel boosted heavy metal removal

Siqi Qi,Min Lin,Pengfei Qi,Junjie Shi,Ge Song,Wenxin Fan,Kunyan Sui,Congjie Gao

With the aggravation of pollutants damage to the environment, it is crucial yet rather challenging to design powerful matrixes for nanomaterials with high ions permeability and migration, as well as multiple exposed active sites. However, most of the current nanomaterial matrixes just act as carrier supporters with introduced invalid mass. Here, a gradient natural polycation electrolyte (chitosan) hydrogel was engineered as nanomaterials matrix to boost anionic heavy metals removal such as antimonate (Sb(V)) and arsenate (As(V)) for the first time, based on the generated interfacial and build-in electric potentials due to the diffusion of counterions. The resulting dual electric potentials allow for rapid diffusion and removal efficiency of heavy metal ions. Exemplified by Sb(V) removal, the chitosan gradient hydrogel matrixes with embedded UiO-66 MOFs exhibited a 3-fold higher removal velocity than the homogeneous hydrogel matrix, and their removal efficiencies were also promoted by gathering on the high charge density side of hydrogels. In contrast to the other reported matrix materials without driving force, the gradient polyelectrolyte hydrogel can greatly boost the removal efficiency and shorten the treatment times. This study offers inspirations on eliminating heavy metal contaminations based on self-driving forces stemming from the heterogeneous structure of materials.

One-step purification of ethylene from ethane/ethylene mixtures by a stable vanadium-based metal-organic framework

Meiling Li,ShanShan Mao,Xin Zhou,Hao Wang

The efficient separation of ethylene (C 2 H 4 ) from ethane/ethylene (C 2 H 6 /C 2 H 4 ) mixtures, achieved via a single-step selective adsorption process, represents a promising yet challenging goal. Notably, the pursuit of adsorbents that combine high adsorption capacity with low adsorption heat is paramount, as these attributes directly correlate with superior separation efficiency and minimized regeneration energy. In this study, we present the selective adsorption of C 2 H 6 over C 2 H 4 by a V-MOF (V-TBAPy), constructed from [V( μ 2 -O)O 4 ] n secondary building units. The pore surface of V-TBAPy is characterized by a high density of aromatic rings and oxygen atoms, which facilitates targeted adsorption of C 2 H 6 through C-H···π and C-H···O interactions. V-TBAPy adsorbs up to 102.6 cm 3 /g of C 2 H 6 at 298 K and 1 bar, with a selectivity of 1.66 for an equimolar C 2 H 6 /C 2 H 4 binary mixture. Importantly, the adsorption heat for C 2 H 6 on V-TBAPy is as low as 22.7 kJ/mol, enabling energy-efficient regeneration. Breakthrough experiments have confirmed the efficacy of V-TBAPy in achieving one-step purification of C 2 H 6 /C 2 H 4 mixtures in conditions mimicking industrial settings.

Highly efficient separation and recovery of Si, V, and Cr from V-Cr-bearing reducing slag

Yun Guo,Hong-Yi Li,Jie Cheng,Shuo Shen,Jiang Diao,Bing Xie

The V-Cr-bearing reducing slag (VCBRS) is solid waste, which cannot be treated at present. This work proposes an effective approach to separately recover its major elements of V, Cr and Si and fully utilize the VCBRS with added-values. Flocculation desiliconization is used to extract Si from the acid solving liquid of VCBRS and Si is recovered as white carbon black with purity of 94.60% and recovery of 93.04%. After desiliconization, V in the solving liquid is selectively oxidized by H 2 O 2 and extracted by microemulsion extraction, which is recovered as V 2 O 5 whose purity is 99.60% with recovery at 96.32% from the stripping liquor of loaded microemulsion . Cr in the raffinate is recovered by alkaline precipitation as final product of Cr 2 O 3 with purity of 98.83% and recovery of 92.68%. The principles are discussed in detail and the operation conditions are optimized systematically. The microemulsion and wastewater are both cyclically utilized, which eliminates the secondary wastes. This work efficiently recovers all valuable elements with increased values from the solid waste, which can not only solve the environmental pollution problem, but also realize the efficient recovery of valuable elements to achieve comprehensive utilization.

Biosorption of V(V) onto Lantana camara biochar modified by H3PO4: Characteristics, mechanism, and regenerative capacity

Kexin Chen,Danni Ma,Haoyang Yu,Shan Zhang,Barnabas C. Seyler,Zimo Chai,Shuming Peng

Biochar has been widely recognized as an environmentally efficient adsorbent for removing heavy metals. However, considering the weak adsorption performance of the original biochar to the oxygen-containing anion, the adsorption of vanadium by biochar has rarely been investigated. This study proposes that H 3 PO 4 activated biochar made from an invasive plant species growing near mines is a novel material to be investigated for V(V) recovery and reuse. As a noxious, invasive plant, Lantana camara L. (LC) has become widely naturalized around the world. Biochar was prepared from LC by pyrolysis at different conditions (200 °C, 350 °C, 500 °C, and 650 °C). The adsorption effect of biochar with and without P pretreatment on V(V) in aqueous solution was compared. The results show that biochar prepared from LC impregnated with H 3 PO 4 (MLBC) had the highest adsorption capacity at 500 °C, and the maximal adsorption capacity fitted by Langmuir model was 77.38 mg g −1 , which was considerably higher than that of untreated biochar (LBC, 5.89 mg g −1 ). The adsorption procedure was substantially fitted by the Langmuir isotherm and the pseudo-second-order kinetic. Additionally, the interaction of V(V) on MLBC is pH-dependent, and slightly acidic conditions are more favorable for adsorption. The characterization results indicated that electrostatic interaction, complexation reaction, and redox reaction were the primary mechanisms. After three cycles of adsorption, the final maximal adsorption capacity of MLBC remained at 76.03% of that of the virgin sample, demonstrating that MLBC had a recyclable capability to eliminate and restore V(V) from aqueous solutions.

Biochar-supported zero-valent iron enhanced arsenic immobilization in a paddy soil: the role of soil organic matter

Wang Shengsen,Li Wenjing,Ding Chengyu,Zhang Jian,Zhang Ni,Li Yuncong C.,Gao Bin,Wang Bing,Wang Xiaozhi

Arsenic (As) detoxification in polluted soils by iron-based materials can be mediated by the endogenous soil organic matter (SOM), nevertheless the mechanisms remain unclear. Herein, endogenous SOM in a paddy soil was substantially removed to understand its roles on As immobilization by biochar-supported zero-valent iron (ZVI/BC). The results demonstrated that ZVI/BC application significantly decreased As bioavailability by 64.2% compared with the control soil under the anaerobic condition. XPS and HR-TEM suggested As immobilization by ZVI/BC mainly invoked the formation of ternary complexes (i.e., As-Fe-SOM). However, SOM depletion compromised the efficacy of ZVI/BC for As immobilization by 289.8%. This is likely because SOM depletion increased the fulvic acid and OH − contents in soils. Besides, ZVI/BC increased the proportion of As(III) in available As fraction, but SOM depletion altered the mechanisms associated with As(V) reduction. That is, As(V) reduction resulted from the reductive capacity of ZVI in the pristine soil, but the As(V)-reducing bacteria contributed greater to As(V) reduction in the SOM-depleted soil. Additionally, SOM depletion boosted the abundances of Fe(III)- and As(V)-reducing bacteria such as Bacillus and Ammoniphilus in soils, which enhanced the dissimilatory arsenate reduction. Thus, this work highlighted the importance of SOM in the remediation of As-contaminated soils by ZVI/BC. Graphical Abstract

PART V: GUIDE TO NEW RESOURCES

Ming Fang He,Jeff Sapp,Edwidge Bryant,Pamela Taylor,Betty Christine Eng

Adsorption behavior and removal mechanism of arsenic on graphene modified by iron–manganese binary oxide (FeMnOx/RGO) from aqueous solutions

Jin Zhu,Zimo Lou,Yu Liu,Ruiqi Fu,Shams Ali Baig,Xinhua Xu

Iron–manganese binary oxide (FeMnOx) is considered highly effective for arsenic adsorption, however, the agglomeration effect hindered its practical application. In this study, graphene has been used as a supporting matrix to disperse FeMnOx due to its huge specific surface area, and the synthesized novel composite adsorbent (FeMnOx/RGO) was employed for arsenic removal. Results demonstrated that FeMnOx/RGO (mass ratio of FeMnOx to FeMnOx/RGO nanocomposites is 45%) has larger specific surface area (411 m2 g−1) in comparison with bare FeMnOx, and showed 10.16 mg As g−1 FeMnOx and 11.49 mg As g−1 FeMnOx adsorption capacities for As(III) and As(V), respectively, with 1 mg L−1 initial concentration. Increased in the initial concentration to 7 mg L−1, the adsorption capacities of As(III) and As(V) reached to 47.05 mg As g−1 FeMnOx and 49.01 mg As g−1 FeMnOx, respectively. The removal process perfectly obeys pseudo second-order kinetic model for both As(III) and As(V). And PO43− was found to strongly inhibit arsenic adsorption. Furthermore, adsorption tests and characterization analyses confirmed that MnO2 played a key role on the oxidation of As(III), while iron(III) oxide was found crucial to As(V) removal. Electrostatic interaction and surface complexation mechanisms involved in the adsorption. These findings suggested that the adsorbent could be used in real arsenic-contaminated water treatment.