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1.
Food Chem ; 370: 131031, 2022 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-34509153

RESUMO

To determine whether high spraying concentrations of Zn sources increase the Zn concentration in waxy corn (Zea mays L. var. ceratina Kulesh) seeds without compromising agronomic performance, field experiments were conducted between 2018 and 2020. Excess ZnSO4 application caused foliar burn, barren ear tip, and grain yield loss. ZnEDTA and Glycine-chelated Zn (ZnGly) caused less foliar burn, but Glycine-mixed Zn caused more foliar burn than ZnSO4. The seed Zn concentration increased with spraying Zn concentration. ZnEDTA (≤0.8%) had a higher threshold concentration than ZnGly (≤0.4%). Nevertheless, Zn biofortification efficacy did not significantly differ between 0.4% ZnGly and 0.8% ZnEDTA, and the grain Zn recovery rate of 0.4% ZnGly was much higher than that of 0.8% ZnEDTA. Additionally, dual-isotope labelling tests confirmed that 15N-glycine and 68Zn in ZnGly interacted. In the future, chelating technology is essential for developing new Zn fertilizers to optimize Zn biofortification efficacy.


Assuntos
Biofortificação , Sulfato de Zinco , Animais , Abelhas , Glicina/toxicidade , Ceras , Zea mays , Zinco
2.
Sci Total Environ ; 803: 150036, 2022 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-34525718

RESUMO

Thallium (Tl) is a highly toxic trace metal. Lead (Pb)­zinc (Zn) smelting, which is a pillar industry in various countries, is regarded as one of the dominant anthropogenic sources of Tl contamination in the environment. In this study, thallium isotope data have been evaluated for raw material and a set of industrial wastes produced at different stages of Pb-Zn smelting in a representative large facility located by the North River, South China, in order to capture Tl isotope signatures of such typical anthropogenic origin for laying the foundation of tracking Tl pollution. Large variations in Tl isotopic compositions of raw Pb-Zn ores and solid smelting wastes produced along the process chain were observed. The ε205Tl values of raw Pb-Zn ores and return fines are -0.87 ± 0.26 and -1.0 ± 0.17, respectively, contrasted by increasingly more negative values for electrostatic precipitator dust (ε205Tl = -2.03 ± 0.14), lime neutralizing slag (ε205Tl = -2.36 ± 0.18), and acid sludge (ε205Tl = -4.62 ± 0.76). The heaviest ε205Tl (1.12 ± 0.51) was found in clinker. These results show that isotopic fractionation occurs during the smelting processes. Obviously, the lighter Tl isotope is enriched in the vapor phase (-3.75 ε205Tl units). Further XPS and STEM-EDS analyses show that Tl isotope fractionation conforms to the Rayleigh fractionation model, and adsorption of 205Tl onto hematite (Fe2O3) may play an important role in the enrichment of the heavier Tl isotope. The findings demonstrate that Tl isotope analysis is a robust tool to aid our understanding of Tl behavior in smelting processes and to provide a basis for source apportionment of Tl contaminations.


Assuntos
Tálio , Zinco , Monitoramento Ambiental , Resíduos Industriais , Isótopos/análise , Chumbo , Tálio/análise
3.
Sci Total Environ ; 803: 149866, 2022 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-34525768

RESUMO

Heavy metal (HM) soil pollution has become an increasingly serious problem with the development of industries. Application of biochar in HMs remediation from contaminated environment has attracted considerable research attention during the past decade. Although the mechanism of HMs passivation with biochar has been investigated, effects and mechanisms of interaction among soil-indigenous microbes and novel carbon matrix composites for HMs adsorption and passivation are still unclear. Four different biochar-loaded aerogels, namely, BNCA-1-600, BNCA-1-900, BNCA-2-600, and BNCA-2-900, were synthesized in this study. Adsorption capacity of four kinds of synthetic materials and two types of contrast biochars (BC600 and BC900) to HMs in aqueous solution, passivation capacity of HMs in soil, and effects on soil organic matter and microbial community were explored. Results showed that BNCA-2-900 exhibits excellent adsorption property and a maximum removal capacity of 205.07 mg·g-1 at 25 °C for Pb(II), 105.56 mg·g-1 for Cd(II), and 137.89 mg·g-1 for Zn(II). Leaching concentration of HMs in contaminated soil can meet the national standard of China (GB/T 5085.3-2007) within 120 days. Results of this study confirmed that the additive BNCA-2-900 and coexistence of indigenous microorganisms can effectively reduce bioavailability of HMs. Another potential mechanism may be to remove the passivation of HMs by porous structure and surface functional groups as well as improve the content of organic matter and microbial abundance. The research results may provide a novel perceptive for the development of functional materials and strategies for eco-friendly and sustainable multiple HMs remediation in contaminated soil and water by using a combination of carbon matrix composites and soil-indigenous microorganisms.


Assuntos
Metais Pesados , Microbiota , Nanopartículas , Poluentes do Solo , Carvão Vegetal , Chumbo , Metais Pesados/análise , Solo , Poluentes do Solo/análise , Zinco
4.
Sci Total Environ ; 803: 150006, 2022 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-34487902

RESUMO

Soil contamination with trace metal(loid) elements (TME) is a global concern. This has focused interest on TME-tolerant plants, some of which can hyperaccumulate extraordinary amounts of TME into above-ground tissues, for potential treatment of these soils. However, intra-species variability in TME hyperaccumulation is not yet sufficiently understood to fully harness this potential. Particularly, little is known about the rhizosphere microbial communities associated with hyperaccumulating plants and whether or not they facilitate TME uptake. The aim of this study is to characterize the diversity and structure of Arabidopsis halleri rhizosphere-influenced and background (i.e., non-Arabidopsis) soil microbial communities in four plant populations with contrasting Zn and Cd hyperaccumulation traits, two each from contaminated and uncontaminated sites. Microbial community properties were assessed along with geographic location, climate, abiotic soil properties, and plant parameters to explain variation in Zn and Cd hyperaccumulation. Site type (TME-contaminated vs. uncontaminated) and location explained 44% of bacterial/archaeal and 28% of fungal community variability. A linear discriminant effect size (LEfSe) analysis identified a greater number of taxa defining rhizosphere microbial communities than associated background soils. Further, in TME-contaminated soils, the number of rhizosphere-defining taxa was 6-fold greater than in the background soils. In contrast, the corresponding ratio for uncontaminated sites, was 3 and 1.6 for bacteria/archaea and fungi, respectively. The variables analyzed explained 71% and 76% of the variance in Zn and Cd hyperaccumulation, respectively; however, each hyperaccumulation pattern was associated with different variables. A. halleri rhizosphere fungal richness and diversity associated most strongly with Zn hyperaccumulation, whereas soil Cd and Zn bioavailability had the strongest associations with Cd hyperaccumulation. Our results indicate strong associations between A. halleri TME hyperaccumulation and rhizosphere microbial community properties, a finding that needs to be further explored to optimize phytoremediation technology that is based on hyperaccumulation.


Assuntos
Arabidopsis , Microbiota , Poluentes do Solo , Biodegradação Ambiental , Cádmio , Rizosfera , Solo , Microbiologia do Solo , Poluentes do Solo/análise , Zinco
5.
Chemosphere ; 286(Pt 1): 131678, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34346324

RESUMO

The establishment of vegetation cover is an important strategy to reduce wind and water erosion at metal smelting waste slag sites. However, the mobility of heavy metals in waste slag-vegetation-leachate systems after the application of revegetation strategies is still unclear. Large microcosm experiments were conducted for revegetation of waste slag for 98 d using combined amendments, i.e., phosphate rock and an organic waste coming from the anaerobic digestion of pig manure (named as biogas residue), and by single- and co-planted perennial ryegrass (Lolium perenne L.) and Trifolium repens (T. repens). The results showed that the application of biogas residue slightly increased the concentrations of Zn and Cd in the leachates; however, the establishment of plants could avoid the excessive leaching of heavy metals coming from the biogas residue. The bioavailability of Cu, Zn, and Cd slightly increased, but Pb bioavailability significantly decreased regardless of single- or co-planting patterns. Additionally, the bioavailability of Cu, Zn, and Cd in the waste slag revegetated with perennial ryegrass was lower than that in T. repens under the single-planting pattern. The change in the heavy metals bioavailability under different revegetation strategies was mainly due to the root-induced change in the pH and speciation of heavy metals in the waste slag. The application of biogas residue and phosphate rock tends to the immobilization of Pb. Heavy metals mainly accumulated in the underground parts of the two herbs, and the heavy metal contents in the underground parts of perennial ryegrass were higher than those in T. repens regardless of single- or co-planting patterns. The heavy metals accumulated in T. repens were lower than those in perennial ryegrass in the single-planting pattern. The bioaccumulation and transportation factors of the two herbs were extremely low. Thus, the two herbs are potential candidates for phytostabilization of zinc smelting waste slag sites.


Assuntos
Lolium , Metais Pesados , Poluentes do Solo , Animais , Biodegradação Ambiental , Metais Pesados/análise , Poluentes do Solo/análise , Suínos , Zinco/análise
6.
Sci Total Environ ; 802: 149905, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34525710

RESUMO

Immobilizing heavy metals (HMs) from municipal solid waste incineration fly ash (MSWIFA) using shell coal gasification fly ash (SFA)-based geopolymer can solve the energy and environmental challenges simultaneously. In this study, we synthesized a geopolymer with SFA, metakaolin (MK), and steel slag (SS) to solidify and stabilize HMs (Pb, Cr, and Zn) and investigated the early immobilization mechanisms. The results show that the prepared geopolymer possessed high early-age mechanical strength and immobilization efficiency to HMs (>90%), even under the effect of excess HMs. The early immobilization mechanism of the geopolymer for the HMs could be described as follows. (1) Most of HMs were remained in the aluminosilicate. (2) The presence of amorphous zeolite precursor and clay minerals may contribute to restrain the HMs leaching; (3) Pb and Zn were trapped by the gel structure in M-O-Al and M-O-Si forms (M = Pb or Zn), whereas Cr (VI) was reduced to Cr (III). (4) Cr might involve in the geopolymerization of [SiO4] and [AlO4]- units. (5) The immobilization process of Pb and Zn in the geopolymer could be described as crystal growth (NG) - phase boundary reaction (I) - NG - I - diffusion (D), whereas that of Cr is prolonged to NG-I-NG-I-NG-I-D.


Assuntos
Metais Pesados , Eliminação de Resíduos , Carbono , Carvão Mineral , Cinza de Carvão , Incineração , Chumbo , Metais Pesados/análise , Material Particulado , Resíduos Sólidos , Zinco
7.
Sci Total Environ ; 802: 149949, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34525744

RESUMO

Biochar is a popular material that would effectively immobilize heavy metals in soil, which can greatly decrease the health risk of heavy metals. Although many previous studies have studied the immobilization of heavy metals by biochar, the influence of hydrological conditions on the immobilization effect is still not clear. This paper carried out column experiments to study the effect of fluctuating groundwater table on Cu, Ni, Pb, Zn distribution and speciation with the addition of biochar from pyrolysis of swine manure. Experimental results showed that biochar could significantly decrease the leaching toxicity of Cu and Ni by 24.4% and 44.7% respectively, while the immobilization effect of Pb and Zn was relatively insignificant. The average reduction percentage of bioavailable Cu was 14.5%, 39.5% and 33.3% in the unsaturated zone, fluctuating zone and saturated zone respectively, showing the better immobilization effect in the fluctuating zone and saturated zone. The residual fraction of heavy metals increased significantly after the addition of biochar, and the increase of residual fraction was larger in small soil aggregates. This study helped illustrate the influence of hydrological conditions and soil aggregate sizes on the stabilization effect of heavy metals by biochar, which could be used to guide the remediation process of sites contaminated by heavy metals.


Assuntos
Metais Pesados , Poluentes do Solo , Animais , Carvão Vegetal , Chumbo , Metais Pesados/análise , Solo , Poluentes do Solo/análise , Suínos , Zinco
8.
Spectrochim Acta A Mol Biomol Spectrosc ; 264: 120329, 2022 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-34481251

RESUMO

Belonging to the Sartan family, antihypertensive drug - Valsartan (Val) had been found to possess antioxidant properties. Also, the zinc complex of Valsartan (VZn) has been recently recognized as inducing agents of the reductive stress effects thus possessing anticancer activity. Hence, in this work an attempt has been made to understand the interaction of Val and VZn with DNA using spectroscopic and in silico methods as DNA has been identified as the target for many anticancer drugs. VZn has been prepared in 2:1 M ratio and characterised by absorbance, FTIR, HRMS, NMR and Job's continuous variation method. VZn has been tested against human lungs cancer cell line which exhibited good anticancer activity (IC50 = 89 µg/mL). Interaction of Val and VZn with ct-DNA under physiological conditions has been studied by spectroscopic techniques such as fluorescence, absorbance, FTIR, circular dichroism (CD) and in silico methods. Fluorescence quenching, DNA melting and viscometric studies confirmed that both ligand and complex bind to the grooves of the ct-DNA. The experimental results have revealed that VZn strongly bind with DNA compared to Val. Docking study suggested that, Val binds at major groove while VZn binds to both minor and major grooves of B-DNA.


Assuntos
DNA , Zinco , Dicroísmo Circular , Simulação por Computador , Humanos , Simulação de Acoplamento Molecular , Espectrometria de Fluorescência , Valsartana
9.
Spectrochim Acta A Mol Biomol Spectrosc ; 264: 120232, 2022 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-34352500

RESUMO

To achieve the ultrastable LMOFs with predominant luminescent sensing performances, the aromatic π-electron mixed ligands strategy was introduced, and the ternary LMOF of {[Zn2(HDDB)(bib)1.5]·3H2O}n (1), was fabricated based on 3,5-di(2',4'-dicarboxylphenyl)benozoic acid (H5DDB) and the N-donor of meta-bis(imidazol-1-yl)benzene (bib) under mixed solvothermal condition. LMOF 1 features the first reported 3D 3,4,4-c {62.83.10}{62.8}2{63.82.10}2 framework with 21.2 % porosity as well as high thermal and chemical stability. Further luminescent sensing showed that LMOF 1 as a bifunctional chemosensor possessing predominant detectability for sensitive detect the hexavalent chromates and nitroimidazoles/nitrofurans antibiotics in water through strong luminescent quenching effects, with excellent reusability as well as trace detection limits. Moreover, luminescent quenching mechanisms were further investigated from electron transfer and energy transfer viewpoints.


Assuntos
Antibacterianos , Zinco , Ânions , Antibacterianos/análise , Cromo , Água
10.
J Hazard Mater ; 421: 126720, 2022 01 05.
Artigo em Inglês | MEDLINE | ID: mdl-34343883

RESUMO

An emerging global necessity for alternative resources combined with maximum catalytic efficiency, low cost, and eco-friendly composite remains a hotspot in the scientific society. Hereby, a novel protocol is approached to design a heterostructure of Zinc MOF decorated on the surface of 2D activated carbon (AC) through a simplistic approach. To begin with, analytical, morphological and spectroscopical studies were performed to identify the functional moieties, cruciate-flower like morphology and oxidative state of atoms present in the composite Zn-MOF @AC. The photocatalytic material aids in degrading both cationic and anionic dye in a UV (254 nm) irradiated environment at a rate of 86.4% and 77.5% within 90 mins. Subsequently, the hybrid materials are coated on the carbon substrate to evaluate the catalytic activity using oxygen evolution and reduction reaction process. The mechanical insight for the catalytic activity relies on the electronic transitions of atoms on the edges of the sheets ascribing to d-d energy levels between the interfacial electron movement. Our composite exhibits an overpotential of 0.7 V and a Tafel slope of 70 mV/dec for the oxygen reduction reaction. This study proposes an alternate approach for developing MOF decorated carbon-based composites for photocatalytic degradability and energy necessity.


Assuntos
Carvão Vegetal , Oxigênio , Catálise , Oxirredução , Zinco
11.
Food Chem ; 368: 130773, 2022 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-34399183

RESUMO

The presence of antinutrients in common beans negatively affects mineral bioavailability. Therefore, this study aimed to predict the antinutrient to mineral molar ratios (proxy-indicators of in vitro mineral bioavailability) of a wide range of raw bean types, using near-infrared (NIR) spectroscopy. Iron, zinc, phytate and tannin concentrations and, antinutrient to mineral molar ratios were determined. Next, model calibration using NIR spectra from milled beans was performed. This entailed wavelength selection, pre-processing and partial least squares regression. Bean type had a significant effect on tannin content. The average values of phytate to iron (Phy:Fe), phytate to zinc (Phy:Zn), tannins to iron (Tan:Fe) and phytate and tannins to iron (Phy + Tan:Fe) MRs were 27.6, 61.7, 16.0 and 43.6, respectively. With determination coefficients for test set prediction above 75%, the PLS-R models for Phy:Zn, Tan:Fe and Phy + Tan:Fe molar ratios are useful for screening purposes.


Assuntos
Phaseolus , Minerais , Ácido Fítico , Espectroscopia de Luz Próxima ao Infravermelho , Zinco
12.
J Colloid Interface Sci ; 606(Pt 2): 1014-1023, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34487924

RESUMO

An outstanding oxygen reduction reaction (ORR) electrocatalyst is firstly developed deriving from sustainable rice husk (RH) biomass. Benefiting from self-doped Si in RH, the higher proportion of pyridine N, graphite N and expecially Fe-Nx as well as thiophene S contents were produced in Si-Fe/S/N-RH3 in comparison with those of Si-free Fe/S/N-RH3. Consequently, the half-wave potential of 0.89 V and the onset potential of 0.96 V are achieved for Si-Fe/S/N-RH3, outperforming the benchmark electrocatalyst Pt/C and other Fe-based electrocatalysts reported in alkaline media. Furthermore, it is found that the exisentence of self-doped Si can improve the graphitization degree of the catalyst, leading to the long-term stability (larger than 85% retention after 40000 s) and prominent methanol tolerance for Si-Fe/S/N-RH3. In addition, Si-Fe/S/N-RH3 shows a power density of 86.2 mW cm-2 and excellent durability in Zn-air battery. The work highlights the potential to develop sustainable and cost-effective ORR electrocatalysts from waste biomass as the substitute for precious metal catalysts.


Assuntos
Oryza , Biomassa , Fontes de Energia Elétrica , Oxigênio , Zinco
13.
J Colloid Interface Sci ; 606(Pt 2): 1031-1041, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34487926

RESUMO

The development of sensitive and selective sensors using facile and low-cost methods for detecting neurotransmitter molecules is a critical factor in the health care system in regard to early diagnosis. In this research, an electrocatalyst derived from Mo,Zn dual-doped CuxO nanocrystals-based layer coating over one-dimensional copper nanowire arrays (Mo,Zn-CuxO/CuNWs) was successfully designed using a facile electrodeposition approach and used as an electrochemical sensor for non-enzymatic dopamine (DA) neurotransmitter detection. The synergistic effect caused by the dual-doping effect along with its excellent conductivity produced a large electroactive surface area and an improved hetero-charge transfer, thereby boosting DA sensing ability with a low limit detection of 0.32 µM, wide-range of detection (0.5 µM - 3.9 mM), long-term stability (5 weeks), and high selectivity in phosphate buffer solution (pH 7.4). Also, the sensor accurately determined DA in real blood serum-spiked solutions. The achieved results evidenced that the Mo,Zn-CuxO/CuNWs derived sensor is highly suitable for DA detection. Therefore, it also opens new windows for the development of low-cost, accurate, high-performance, and stable sensors for other neurotransmitter sensing for the purposes of better health care and early diagnosis.


Assuntos
Técnicas Eletroquímicas , Nanopartículas , Cobre , Neurotransmissores , Zinco
14.
Environ Pollut ; 292(Pt B): 118414, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34728325

RESUMO

Incidental zinc sulfide nanoparticles (nano-ZnS) are spread on soils through organic waste (OW) recycling. Here we performed soil incubations with synthetic nano-ZnS (3 nm crystallite size), representative of the form found in OW. We used an original set of techniques to reveal the fate of nano-ZnS in two soils with different properties. 68Zn tracing and nano-DGT were combined during soil incubation to discriminate the available natural Zn from the soil, and the available Zn from the dissolved nano-68ZnS. This combination was crucial to highlight the dissolution of nano-68ZnS as of the third day of incubation. Based on the extended X-ray absorption fine structure, we revealed faster dissolution of nano-ZnS in clayey soil (82% within 1 month) than in sandy soil (2% within 1 month). However, the nano-DGT results showed limited availability of Zn released by nano-ZnS dissolution after 1 month in the clayey soil compared with the sandy soil. These results highlighted: (i) the key role of soil properties for nano-ZnS fate, and (ii) fast dissolution of nano-ZnS in clayey soil. Finally, the higher availability of Zn in the sandy soil despite the lower nano-ZnS dissolution rate is counterintuitive. This study demonstrated that, in addition to nanoparticle dissolution, it is also essential to take the availability of released ions into account when studying the fate of nanoparticles in soil.


Assuntos
Nanopartículas , Poluentes do Solo , Isótopos , Solo , Poluentes do Solo/análise , Sulfetos , Espectroscopia por Absorção de Raios X , Zinco/análise , Compostos de Zinco
15.
J Colloid Interface Sci ; 606(Pt 1): 544-555, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34416450

RESUMO

Photocatalysts with highly efficient charge separation are of critical significance for improving photocatalytic hydrogen production performance. Herein, a cost-effective and high-performance composite photocatalyst, cobalt-phosphonate-derived defect-rich cobalt pyrophosphate hybrids (CoPPi-M) modified Cd0.5Zn0.5S is rationally devised via defect and interface engineering, in which the co-catalyst CoPPi-M delivers a strong interaction with host photocatalyst Cd0.5Zn0.5S, rendering Cd0.5Zn0.5S/CoPPi-M with a remarkably improved efficiency of charge separation and migration. Besides, Cd0.5Zn0.5S/CoPPi-M exhibits a hydrophilic surface with ample access to electrons and a strong reduction ability of electrons. Benefiting from these advantages, the integration of defect-rich cobalt pyrophosphate and Cd0.5Zn0.5S enables Cd0.5Zn0.5S/CoPPi-M-5% with high photocatalytic H2 production rate of 6.87 mmol g-1h-1, which is 2.46 times higher than that of pristine Cd0.5Zn0.5S, and the notable apparent quantum efficiency (AQE) is 20.7% at 420 nm. This work provides a promising route for promoting the photocatalytic performance of non-precious hybrid photocatalyst via defect and interface engineering, and advances energy-generation and environment-restoration devices.


Assuntos
Cobalto , Hidrogênio , Cádmio , Difosfatos , Zinco
16.
Chemosphere ; 287(Pt 4): 132457, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34610373

RESUMO

Lead (Pb) is the most widely used anode in zinc (Zn) electrowinning and other metallurgical industries. The resource loss and environmental pollution caused by Pb anode corrosion are urgent problems to be solved. A γ-MnO2 precoated anode was prepared successfully to reduce the Pb-containing pollutant. The size effects with its controllable preparation on an industrial scale were studied. Severe nonuniform distribution of γ-MnO2 film was observed with curbing the reduction of anode slime only 68%, when anode size increased from lab to industry. Nonuniform rate (R) and average thickness (d) were found to be the key indicators to determine the film structure distribution and their performance differences, which were random and difficult to be controlled in scale-up size. However, a controllable industrial γ-MnO2 precoated anodes (IMPA) fabricated through optimized current density (J0) and electrodeposition time (t) in our developed film-forming system. Then, the long-term performances of two IMPA with different indicators (IMPA-1: R = 34%, d = 108 µm, IMPA-2: R = 23%, d = 55 µm) were compared with the industrial typical Pb-based anode (ITPA). Of the three different anodes, the optimized IMPA-2 displayed the best performance. Within 24 d of electrowinning cycle, the corrosion inhibition effect and the anode slime reduction rate for IMPA-2 improved by 56% and 30% than IMPA-1, and improved by 100% and 91% than ITPA. Furthermore, the mechanism analysis of size effect change showed that R of IMPA was contributed to the local gas holdup distribution along the anode. Controlled size effect of uniform oxide film will have a future application prospect for the sustainability of industry, which provides an important cleaner production of Zn electrowinning and related hydrometallurgy industries.


Assuntos
Poluentes Ambientais , Zinco , Eletrodos , Chumbo , Compostos de Manganês , Metalurgia , Óxidos
17.
Chemosphere ; 287(Pt 2): 132238, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34826927

RESUMO

Magnetic binary heterojunctions are a kind of promising photocatalysts due to their high catalytic activity and easy magnetic separation; however, their synthesis may involve high costs or secondary environmental impacts. In this work, the magnetically recyclable Mn0.6Zn0.4Fe2O4@Zn1-xMnxS (MZFO@Zn1-xMnxS, x = 0.00-0.07) photocatalysts are synthesized from spent batteries via a green biocheaching and egg white-assisted hydrothermal method. The as-synthesized photocatalysts have been comprehensively characterized in phase, morphology, texture, optics, photoelectrochemistry and photocatalytic activity. Characterization results indicate that the desired core-shell structure MZFO@Zn1-xMnxS composites are successfully synthesized, theirs absorption intensity in the visible light region is greatly enhanced compared to Zn1-xMnxS. In addition, doped Mn2+ in ZnS host lattice and the staggered bandgap alignment of MZFO and Zn1-xMnxS greatly enhances electron transfer and charge separation in the binary heterojunction system. The optimized MZFO@Zn0.95Mn0.05S shows the highest photodegradation performance toward phenol under the visible light irradiation, with a complete degradation of 25 mg L-1 of phenol within 120 min, and its reactive kinetic constants is about 5.2 and 13.3 times higher than that of pure Zn0.95Mn0.05S and MZFO, respectively. Furthermore, the mechanism and pathways for the degradation of phenol are proposed. In addition, MZFO@Zn0.95Mn0.05S also exhibits a good reusability and high magnetic separation properties after 5 successive cycles. This new material has the advantages of low costs, simple reuse and great potential in application.


Assuntos
Luz , Fenol , Catálise , Fenóis , Zinco
18.
Spectrochim Acta A Mol Biomol Spectrosc ; 266: 120419, 2022 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-34619506

RESUMO

Nitroaromatic compounds (NACs) can lead to various environmental pollution healh problems. In order to effectively recognize and sense NACs, a novel coordination polymers (CPs) with fluorescent characteristic [Zn3(btc)2(tpt)(H2O)2]·4H2O (1) (tpt = tris(4-pyridyl)triazine, H3btc = 1,3,5-benzenetricarboxylic acid) has been triumphantly prepared as an fluorescence probe by solvothermal method. 1 possesses remarkable PH stability ranging from 2.0 to 12.0 and is also stable in different pure organic solvents. It should be noted that 1 manifests a fluorescence quenching response against the detection of selectivity and sensitivity towards 2,4,6-trinitrophenol (TNP) in aqueous solution. It also makes analysis on the limit of detection towards TNP, which is as low as 0.94 µM compared with most reported CPs sensors for TNP. Therefore, 1 can become a satisfactory sensor for TNP detection with remarkable selectivity, strong anti-interference and favorable recyclability. In addition, the quenching mechanisms were also discussed. It was supposed that the mechanisms of photoinduced electron transfer (PET) as well as resonance energy transfer (RET) might be the main influencing factors.


Assuntos
Luminescência , Polímeros , Picratos , Zinco
19.
Chemosphere ; 287(Pt 1): 131986, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34481173

RESUMO

Urban soil pollution by heavy metals (HMs) is a pressing problem in the development of urban agriculture (UA). In this context, the use of amendments, such as biochar, and phytoremediation are considered potentially cost-effective alternatives to conventional methods, and can be also combined to improve the remediation of soils from HMs. A pot experiment was performed to investigate the combined effect of berseem clover (Trifolium alexandrinum, L.) and biochar amendment in remediating a sandy soil collected near a shooting range area co-contaminated with Cd, Cr, Cu, Ni, Pb, and Zn. The biochar, obtained from a wood-chip gasifier fed with a mix of Douglas (Pseudotsuga menziesii, Mirb.) and Black Pine (Pinus nigra, J.F.Arnold) wood, was applied at two rates (0.8% and 1.6%, w/w). Eighteen weeks after sowing, all plants were harvested. The roots and aboveground tissues of the crops were separately collected and analyzed. The tested biochar effectively adsorbed the HMs (Cd, Cr, Cu, Ni, Pb, and Zn) from the soil. Biochar increased DW production of aboveground and root tissues. Moreover, biochar significantly reduced the concentration of Cr, Cu, Ni, and Pb in the aboveground tissues of berseem clover, although a significant reduction was not detected for Cd and Zn. Results indicated that berseem clover was a Cr, Ni and Pb excluder. However, this species can be considered suitable for Cu phytoextraction and Cd and Zn phytostabilization of slightly polluted urban soil. Only the Cu levels in the aerial biomass were below the acceptable limit for use as fodder.


Assuntos
Metais Pesados , Poluentes do Solo , Trifolium , Biodegradação Ambiental , Cádmio , Carvão Vegetal , Chumbo , Medicago , Metais Pesados/análise , Solo , Poluentes do Solo/análise , Zinco
20.
Chemosphere ; 287(Pt 1): 132122, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34523454

RESUMO

This study is focused on the evaluation of the accumulation of Cd, Pb and Zn in five cultivars of Cichorium intybus L. (chicory) which were produced on contaminated agricultural soil. Over a growth period of 211 days, the roots and leaves were collected in four stages and then analyzed by flame atomic absorption spectrometry to measure the concentration and distribution of the target metals in these two chicory organs considering the weather and the nature of the cultivar. For all cultivars, sharp decreases of Pb (from 165 mg kg-1 to 3 mg kg-1), Cd (from 11 mg kg-1 to 5 mg kg-1) and Zn concentrations (from 157 mg kg-1 to 40 mg kg-1) in the roots were highlighted over time. The data collected enabled the calculation of the variation of the bioconcentration factor, the biological absorption coefficient and the translocation factor for Cd, Pb and Zn. These parameters were then correlated with the distribution of the fresh biomass of leaves and roots and several indicators such as chlorophyll content, flavonols, anthocyanin and nitrogen balance index were measured. The study concludes with the discussion on the ability of chicory to clean up contaminated agricultural soil. The current investigation has shown: i) a translocation of Cd (and Zn to a lesser extent) from the roots to the leaves; ii) an increase in the level of anthocyanins with the increase of the metal trace elements concentration in the leaf, while the content of chlorophyll and the nitrogen balance index decrease, which could be linked to the phenomenon of senescence; iii) an ability of the chicory to reduce the bioavailable pool of the three metal trace elements studied, in particular for Cd.


Assuntos
Chicória , Metais Pesados , Poluentes do Solo , Antocianinas , Biodegradação Ambiental , Cádmio/análise , Chumbo , Metais Pesados/análise , Solo , Poluentes do Solo/análise , Zinco/análise
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