Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 133
Filtrar
Mais filtros

Base de dados
País/Região como assunto
Tipo de documento
País de afiliação
Intervalo de ano de publicação
1.
Langmuir ; 40(6): 3222-3230, 2024 Feb 13.
Artigo em Inglês | MEDLINE | ID: mdl-38287218

RESUMO

UiO-66-type metal-organic frameworks have been considered as promising adsorbents for capturing Ag(I) from wastewater. However, uncertainties persist regarding the specific absorptivity of individual functional groups to the UiO-66 framework structure. In this study, UiO-66-type metal-organic frameworks (UiO-66-X), featuring diverse functional groups (X = -(OH)2, -(COOH)2, -NO2, -NH2, -SO3H, -(SH)2), were synthesized in situ for Ag(I) capture. The findings revealed that functionalization significantly enhanced the adsorption capacity of Ag(I). Notably, quantitative analysis showed that 1 mol of -SH functional group onto the UiO-66 framework structure can adsorb 0.73 mol of Ag(I) ions, surpassing those of -COOH, -OH, -NH2, -SO3H, and -NO2 by 2.4-, 3.5-, 3.8-, 9.1-, and 24.3-fold, respectively. This represents the first assessment of the adsorption capacity of functionalized UiO-66 for Ag(I) based on each effective functional group, addressing limitations in traditional unit mass calculations. Further, the adsorption mechanism of UiO-66-X for selectively capturing Ag(I) was elucidated through experimental and theoretical analyses. Additionally, selectivity and practical applications confirm that UiO-66-(SH)2 exhibits strong anti-interference ability, whether in natural water bodies with complex compositions or in industrial wastewater under harsh conditions. We anticipate that this study will enhance our understanding of structure-performance dependencies of multivariate MOFs for designing novel adsorbents for Ag(I) capture.

2.
Environ Sci Technol ; 58(9): 4145-4154, 2024 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-38381076

RESUMO

The deactivation of selective catalytic reduction (SCR) catalysts caused by alkali metal poisoning remains an insurmountable challenge. In this study, we examined the impact of Na poisoning on the performance of Fe and Mo co-doped TiO2 (FeaMobTiOx) catalysts in the SCR reaction and revealed the related alkali resistance mechanism. On the obtained Fe1Mo2.6TiOx catalyst, the synergistic catalytic effect of uniformly dispersed FeOx and MoOx species leads to remarkable catalytic activity, with over 90% NO conversion achieved in a wide temperature range of 210-410 °C. During the Na poisoning process, Na ions predominantly adsorb on the MoOx species, which exhibit stronger alkali resistance, effectively safeguarding the FeOx species. This preferential adsorption minimizes the negative effect of Na poisoning on Fe1Mo2.6TiOx. Moreover, Na poisoning has little influence on the Eley-Rideal reaction pathway involving adsorbed NHx reacting with gaseous NOx. After Na poisoning, the Lewis acid sites were deteriorated, while the abundant Brønsted acid sites ensured sufficient NHx adsorption. As a benefit from the self-defense effects of active MoOx species for alkali capture, FeaMobTiOx exhibits exceptional alkali resistance in the SCR reaction. This research provides valuable insights for the design of highly efficient and alkali-resistant SCR catalysts.


Assuntos
Álcalis , Amônia , Catálise , Ácidos de Lewis , Metais
3.
Environ Sci Technol ; 58(12): 5394-5404, 2024 Mar 26.
Artigo em Inglês | MEDLINE | ID: mdl-38463002

RESUMO

Conventional microalgal-bacterial consortia have limited capacity to treat low-C/N wastewater due to carbon limitation and single nitrogen (N) removal mode. In this work, indigenous synergetic microalgal-bacterial consortia with high N removal performance and bidirectional interaction were successful in treating rare earth tailing wastewaters with low-C/N. Ammonia removal reached 0.89 mg N L-1 h-1, 1.84-fold more efficient than a common microalgal-bacterial system. Metagenomics-based metabolic reconstruction revealed bidirectional microalgal-bacterial interactions. The presence of microalgae increased the abundance of bacterial N-related genes by 1.5- to 57-fold. Similarly, the presence of bacteria increased the abundance of microalgal N assimilation by 2.5- to 15.8-fold. Furthermore, nine bacterial species were isolated, and the bidirectional promotion of N removal by the microalgal-bacterial system was verified. The mechanism of microalgal N assimilation enhanced by indole-3-acetic acid was revealed. In addition, the bidirectional mode of the system ensured the scavenging of toxic byproducts from nitrate metabolism to maintain the stability of the system. Collectively, the bidirectional enhancement system of synergetic microalgae-bacteria was established as an effective N removal strategy to broaden the stable application of this system for the effective treatment of low C/N ratio wastewater.


Assuntos
Microalgas , Águas Residuárias , Microalgas/metabolismo , Desnitrificação , Nitrogênio/metabolismo , Bactérias/metabolismo , Biomassa
4.
Environ Res ; 251(Pt 2): 118688, 2024 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-38493855

RESUMO

The widespread usage of quaternary ammonium compounds (QACs) as disinfectants during the COVID-19 pandemic poses significant environmental risks, such as toxicity to organisms and the emergence of superbugs. In this study, different inorganic salts (NaCl, KCl, CaCl2, MgCl2) were used to induce endophytes LSE01 isolated from hyperaccumulating plants. After five generations of cultivation under 80 g/L NaCl, the minimum inhibitory concentration (MIC) of LSE01 to QACs increased by about 3-fold, while its degradation extent increased from 8% to 84% for C12BDMA-Cl and 5%-89% for C14BDMA-Cl. Transmission electron microscopy (TEM) and three-dimensional fluorescence spectra indicated that the cells induced by high concentration of salt caused plasmolysis and secreted more bound extracellular polymeric substances (B-EPS); these changes are likely to be an important reason for the observed increased resistance and enhanced degradation extent of LSE01 to QACs. Our findings suggest that salt-induction could be an effective way to enhance the resistance and removal of toxic organic pollutants by functional microorganisms.


Assuntos
Endófitos , Compostos de Amônio Quaternário , Salinidade , Compostos de Amônio Quaternário/farmacologia , Testes de Sensibilidade Microbiana , Bactérias/efeitos dos fármacos , Biodegradação Ambiental
5.
Environ Res ; 252(Pt 1): 118775, 2024 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-38548250

RESUMO

Microalgal technology holds great promise for both low C/N wastewater treatment and resource recovery simultaneously. Nevertheless, the advancement of microalgal technology is hindered by its reduced nitrogen removal efficiency in low C/N ratio wastewater. In this work, microalgae and waste oyster shells were combined to achieve a total inorganic nitrogen removal efficiency of 93.85% at a rate of 2.05 mg L-1 h-1 in low C/N wastewater. Notably, over four cycles of oyster shell reuse, the reactor achieved an average 85% ammonia nitrogen removal extent, with a wastewater treatment cost of only $0.092/ton. Moreover, microbial community analysis during the reuse of oyster shells revealed the critical importance of timely replacement in inhibiting the growth of non-functional bacteria (Poterioochromonas_malhamensi). The work demonstrated that the oyster shell - microalgae system provides a time- and cost-saving, environmental approach for the resourceful treatment of harsh low C/N wastewater.


Assuntos
Exoesqueleto , Carbono , Microalgas , Nitrogênio , Ostreidae , Eliminação de Resíduos Líquidos , Águas Residuárias , Animais , Nitrogênio/análise , Nitrogênio/metabolismo , Microalgas/crescimento & desenvolvimento , Águas Residuárias/química , Exoesqueleto/química , Eliminação de Resíduos Líquidos/métodos , Poluentes Químicos da Água/análise
6.
J Environ Manage ; 352: 120021, 2024 Feb 14.
Artigo em Inglês | MEDLINE | ID: mdl-38183916

RESUMO

The global response to lithium scarcity is overstretched, and it is imperative to explore a green process to sustainably and selectively recover lithium from spent lithium-ion battery (LIB) cathodes. This work investigates the distinct leaching behaviors between lithium and transition metals in pure formic acid and the auxiliary effect of acetic acid as a solvent in the leaching reaction. A formic acid-acetic acid (FA-AA) synergistic system was constructed to selectively recycle 96.81% of lithium from spent LIB cathodes by regulating the conditions of the reaction environment to inhibit the leaching of non-target metals. Meanwhile, the transition metals generate carboxylate precipitates enriched in the leaching residue. The inhibition mechanism of manganese leaching by acetic acid and the leaching behavior of nickel or cobalt being precipitated after release was revealed by characterizations such as XPS, SEM, and FTIR. After the reaction, 90.50% of the acid can be recycled by distillation, and small amounts of the residual Li-containing concentrated solution are converted to battery-grade lithium carbonate by roasting and washing (91.62% recovery rate). This recycling process possesses four significant advantages: i) no additional chemicals are required, ii) the lithium sinking step is eliminated, iii) no waste liquid is discharged, and iv) there is the potential for profitability. Overall, this study provides a novel approach to the waste management technology of lithium batteries and sustainable recycling of lithium resources.


Assuntos
Formiatos , Lítio , Metais , Lítio/química , Metais/química , Reciclagem , Eletrodos , Fontes de Energia Elétrica , Ácido Acético
7.
Environ Sci Technol ; 57(11): 4591-4597, 2023 03 21.
Artigo em Inglês | MEDLINE | ID: mdl-36881640

RESUMO

Recovering lithium from lithium batteries (LIBs) is a promising approach for sustainable ternary lithium battery (T-LIB) development. Current lithium recovery methods from spent T-LIBs mainly concentrated on chemical leaching methods. However, chemical leaching relying on the additional acid seriously threatens the global environment and nonselective leaching also leads to low Li recovery purity. Here, we first reported a direct electro-oxidation method for lithium leaching from spent T-LIBs (Li0.8Ni0.6Co0.2Mn0.2O2); 95.02% of Li in the spent T-LIBs was leached under 2.5 V in 3 h. Meanwhile, nearly 100% Li recovery purity was also achieved, attributed to no other metal leaching and additional agents. We also clarified the relationship between lithium leaching and other metals during the electro-oxidation of spent T-LIBs. Under the optimized voltage, Ni and O maintain the electroneutrality in the structure assisting Li leaching, while Co and Mn maintain their valence states. A direct electro-oxidation Li leaching approach achieves high Li recovery purity and meanwhile overcomes the secondary pollution problem.


Assuntos
Lítio , Reciclagem , Metais , Fontes de Energia Elétrica
8.
Environ Sci Technol ; 57(47): 19012-19022, 2023 Nov 28.
Artigo em Inglês | MEDLINE | ID: mdl-37599507

RESUMO

A carbon-based advanced oxidation process is featured for the nonradical electron-transfer pathway (ETP) from electron-donating organic compounds to activated persulfate complexes, enabling it as a green technology for the selective oxidation of organic pollutants in complex water environments. However, the thermodynamic and kinetic behaviors of the nonradical electron-transfer regime had been ambiguous due to a neglect of the influence of pH on the mechanisms. In this study, three kinds of organic pollutants were divided in the carbon-based ETP regime: (i) physio-adsorption, (ii) adsorption-dominated ETP (oxidation rate slightly surpasses adsorption rate), and (iii) oxidation-dominated ETP (oxidation rate outpaces the adsorption rate). The differential kinetic behaviors were attributed to the physicochemical properties of the organic pollutants. For example, the hydrophobicity, molecular radius, and positive electrostatic potential controlled the mass-transfer process of the adsorption stage of the reactants (peroxydisulfate (PDS) and organics). Meanwhile, other descriptors, including the Fukui index, oxidation potential, and electron cloud density regulated the electron-transfer processes and thus the kinetics of oxidation. Most importantly, the oxidation pathways of these organic pollutants could be altered by adjusting the water chemistry. This study reveals the principles for developing efficient nonradical systems to selectively remove and recycle organic pollutants in wastewater.


Assuntos
Poluentes Ambientais , Poluentes Químicos da Água , Elétrons , Oxirredução , Carbono , Termodinâmica , Água
9.
Environ Res ; 236(Pt 1): 116752, 2023 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-37527747

RESUMO

Antimony contamination of tailings from the mining process remain attracted a great amount of concern. In this study, defective UiO-66-X crystal materials are rationally constructed using trifluoroacetic acid and hydrochloric acid as modulators for the removal of Sb(V) from actual tailing sand leachates. XRD and TG characterizations reveal that the number and kind of defects in UiO-66 are influenced by the type of modulators and the addition of trifluoroacetic acid makes UiO-66-TFA contain both cluster and ligand defects. Adsorption experiments show that UiO-66 and UiO-66-HCl achieve 100% removal of Sb(V) at pH 7.5 of the tailing sand leachate, and up to 90% removal of Sb(V) by the three materials at pH 2.5. It is noteworthy that the removal rate of Sb(V) by UiO-66-HCl is still satisfactory even under strongly acidic conditions at pH 0.5, with good potential for practical applications. Four kinetic models are used to fit the adsorption data and the analysis shows that the mechanism of Sb(V) adsorption by three adsorbent is all pseudo-second order and chemisorption acts as an important role in the adsorption process. In addition, the fixed bed adsorption experiments show that the material exhibit good prospects for practical applications.

10.
Environ Res ; 238(Pt 2): 117253, 2023 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-37778599

RESUMO

As a kind of scarce metal, palladium is widely used in many chemical industries. It essential to recover palladium from secondary resources, especially acidic media, owing to high content of palladium in secondary wastes and widespread extraction of palladium via strong acids. Chemically modified carbon materials not only have the advantage of activated carbon but also achieve the precise removal of specific pollutants, which is a kind of adsorption material with broad application prospects. In this direction, we report a solid carbon material named AT-C, which is obtained by one-step synthesis of 2-aminothiazoles grafted to the carbon surface by amidation. The present adsorbent delivers a high palladium adsorption capacity of 178.9 mg g-1, and desirable thermal and chemical stability. The uniform presence of abundant sulfur atoms and CO in the porous network enables AT-C to achieve selective absorption and rapid adsorption kinetics of Pd2+ in the complex water mixture containing many competing ions in the acidic pH range. For the strongly acidic leachates of catalysts, AT-C exhibits outstanding stability in cyclic experiments. Meanwhile, the fixed-bed column test indicates that 1076 bed volumes of the feeding streams can be effectively treated. In addition, AT-C exhibits superior adsorption selectivity, and the recovery efficiency of Pd2+ in actual industrial wastewater is 96.6%. This work realizes an efficient, rapid, and selective removal of palladium under acidic conditions, and provides a reference for complex industrial water treatment and resource recovery of precious metals.


Assuntos
Águas Residuárias , Poluentes Químicos da Água , Paládio , Carvão Vegetal , Tiazóis , Poluentes Químicos da Água/química , Adsorção , Cinética
11.
J Environ Manage ; 328: 116973, 2023 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-36525735

RESUMO

Microalgae appear to be a promising and ecologically safe way for nutrients removal from rare earth tailings (REEs) wastewater with CO2 fixation and added benefits of resource recovery and recycling. In this study, a pilot scale (50 L) co-flocculating microalgae photobioreactor (Ma-PBR) as constructed and operated for 140 days to treat REEs wastewater with low C/N ratio of 0.51-0.56. The removal rate of ammonia nitrogen (NH4+-N) reached 88.04% and the effluent residual concentration was as low as 9.91 mg/L that have met the Emission Standards of Pollutants from Rare Earths Industry (GB 26451-2011). Timely supplementation of trace elements was necessary to maintain the activity of microalgae and then prolonged the operation time. The dominant phyla in co-flocculating microalgae was Chlorophyta, the relative abundance of which was higher than 80%. Tetradesmus belonging to Chlorophyceae was the dominant genus with relative abundance of 80.35%. The results provided a practical support for the scaling-up of Ma-PBR to treat REEs wastewater.


Assuntos
Metais Terras Raras , Microalgas , Águas Residuárias , Fotobiorreatores , Projetos Piloto , Biomassa , Nitrogênio
12.
Molecules ; 28(7)2023 Mar 24.
Artigo em Inglês | MEDLINE | ID: mdl-37049684

RESUMO

Thermal-responsive block copolymers are a special type of macromolecule that exhibit a wide range of applications in various fields. In this contribution, we report a new type of polyacrylamide-based block copolymer bearing pyridine groups of polyethylene glycol-block-poly(N-(2-methylpyridine)-acrylamide; Px) that display distinct salt-induced lower critical solution temperature (LCST) behavior. Unexpectedly, the phase-transition mechanism of the salt-induced LCST behavior of Px block copolymers is different from that of the reported LCST-featured analogues. Moreover, their thermo-responsive behavior can be significantly regulated by several parameters such as salt species and concentration, urea, polymerization degree, polymer concentration and pH values. This unique thermal behavior of pyridine-containing block copolymers provides a new avenue for the fabrication of smart polymer materials with potential applications in biomedicine.

13.
Angew Chem Int Ed Engl ; 62(38): e202308702, 2023 Sep 18.
Artigo em Inglês | MEDLINE | ID: mdl-37471502

RESUMO

Extraction and recovery of lithium from reserves play a critical role in the sustainable development of energy due to the explosive growth of the lithium-battery market. However, the low efficiency of extraction and recovery seriously threatens the sustainability of lithium supply. In this contribution, we fabricate a novel mechanically robust fluorine-rich hydrogel, showing highly efficient Li+ extraction from Li-containing solutions. The hydrogel was facilely fabricated by simple one-pot polymerization of supramolecular nanosheets of fluorinated monomers, acrylic acid and a small amount of chemical crosslinkers. The hydrogel exhibits a remarkable lithium adsorption capacity (Qm Li+ =122.3 mg g-1 ) and can be reused. Moreover, it can exclusively extract lithium ions from multiple co-existing metal ions. Notably, the separation of Li+ /Na+ in actual wastewater is achieved with a surprising separation factor of 153.72. The detailed characterizations as well as calculation showed that the specific coordination of Li-F plays a central role for both of the striking recovery capability and selectivity for Li+ . Furthermore, an artificial device was constructed, displaying high efficiency of extracting lithium in various complex actual lithium-containing wastewater. This work provides a new and promising avenue for the efficient extraction and recovery of lithium resource from complex lithium-containing solutions.

14.
Environ Sci Technol ; 56(1): 78-97, 2022 01 04.
Artigo em Inglês | MEDLINE | ID: mdl-34932343

RESUMO

Persulfate-based nonradical oxidation processes (PS-NOPs) are appealing in wastewater purification due to their high efficiency and selectivity for removing trace organic contaminants in complicated water matrices. In this review, we showcased the recent progresses of state-of-the-art strategies in the nonradical electron-transfer regimes in PS-NOPs, including design of metal and metal-free heterogeneous catalysts, in situ/operando characterization/analytical techniques, and insights into the origins of electron-transfer mechanisms. In a typical electron-transfer process (ETP), persulfate is activated by a catalyst to form surface activated complexes, which directly or indirectly interact with target pollutants to finalize the oxidation. We discussed different analytical techniques on the fundamentals and tactics for accurate analysis of ETP. Moreover, we demonstrated the challenges and proposed future research strategies for ETP-based systems, such as computation-enabled molecular-level investigations, rational design of catalysts, and real-scenario applications in the complicated water environment. Overall, this review dedicates to sharpening the understanding of ETP in PS-NOPs and presenting promising applications in remediation technology and green chemistry.


Assuntos
Poluentes Químicos da Água , Purificação da Água , Catálise , Transporte de Elétrons , Elétrons , Oxirredução , Poluentes Químicos da Água/análise
15.
Environ Sci Technol ; 56(19): 14019-14029, 2022 10 04.
Artigo em Inglês | MEDLINE | ID: mdl-36062466

RESUMO

In electrochemical advanced oxidation processes (EAOPs), the rate-limiting step is the mass transfer of pollutants to the electrodes due to the limited active surface areas. To this end, we established a three-dimensional (3D) EAOP system by coupling conventional graphite electrodes with dispersed carbon nanotubes (CNTs). The electrodes (particularly the anode) induced electric field spontaneously polarized CNTs into dispersed reactive particle electrodes (CNT-PEs) in the solution, which remarkably promoted electrochemical activation of peroxydisulfate (PDS) to generate surface CNT-PDS* complexes and surface-bound radicals (SBRs). Based on the excited potential (ECNT-PEs) at different positions in the 3D electric field, CNT-PEs were activated into three states. (i) ECNT-PEs < Eorganic, CNT-PEs are chemically inert toward DCP oxidation; (ii) Eorganic < ECNT-PEs < Ewater, CNT-PEs will oxidize DCP via an electron-transfer process (ETP); (iii) ECNT-PEs > Ewater, both CNT-PDS* complexes and the anode will oxidize water to produce SBRs. Thus, DCP could be oxidized by CNT-PDS* complexes via ETP to form polychlorophenols on the CNT surface, causing rapid deactivation of the micro-electrodes. In contrast, SBRs attack DCP directly into chloride ions and hydroxylated products, maintaining the surface cleanliness and activity of CNT-PEs for long-term operations.


Assuntos
Poluentes Ambientais , Grafite , Nanotubos de Carbono , Cloretos , Eletrodos , Nanotubos de Carbono/química , Oxirredução , Água
16.
Environ Sci Technol ; 56(14): 10412-10422, 2022 07 19.
Artigo em Inglês | MEDLINE | ID: mdl-35793711

RESUMO

Acid recycling and arsenic recovery from strongly acidic wastewater are goals of the metallurgical industry to reduce carbon emissions. In this study, arsenic was recovered using a hydroxyl-enriched CeO2 adsorbent, and the adsorption mechanism in a strongly acidic solution was investigated. The adsorption capacities of 88.59 mg/g for As(III) and 126.211 mg/g for As(V) at pH 1.0 are the highest reported values to date. It is revealed that the hydroxyl groups on the CeO2 surface can buffer hydrogen ions, and the isoelectric point of the material can be reduced to pH 1.52. The binding energy of arsenic is -1.25 eV for the hydroxyl-enriched CeO2 and -2.24 eV for CeO2 without hydroxyl groups. Additionally, the protonated hydroxyl groups reduce the oxidation energy of As(III) and promote the adsorption of arsenic by forming new active sites in the strongly acidic solution. Nearly 98.11% of arsenic (initial concentration is 886.8 mg/L) is removed within 24 h without pH adjustment, indicating the feasibility of hydroxyl-enriched CeO2 for recovering arsenic and acid. This work investigated the adsorption and proton-enhanced oxidation mechanism of arsenic by hydroxyl-enriched CeO2 in strongly acidic wastewater.


Assuntos
Arsênio , Cério , Poluentes Químicos da Água , Adsorção , Arsênio/química , Concentração de Íons de Hidrogênio , Radical Hidroxila , Prótons , Águas Residuárias , Poluentes Químicos da Água/química
17.
Environ Sci Technol ; 56(16): 11718-11728, 2022 08 16.
Artigo em Inglês | MEDLINE | ID: mdl-35917327

RESUMO

With the fast development of modern industries, scarcity of freshwater resources caused by heavy metal pollution (i.e., Hg2+) has become a severe issue for human beings. Herein, a 3D-MoS2 sponge as an excellent absorbent is fabricated for mercury removal due to its multidimensional adsorption pathways, which decreases the biomagnification effect of methylmercury in water bodies. Furthermore, a secondary water purification strategy is employed to harvest drinkable water with the exhausted adsorbents, thus alleviating the crisis of drinking water shortage. Compared to the conventional landfill treatment, the exhausted MoS2 sponge absorbents are further functionalized with a poly(ethylene glycol) (PEG) layer to prevent the heavy metals from leaking and enhance the hydrophilicity for photothermal conversion. The fabricated evaporator displays excellent evaporation rates of ∼1.45 kg m-2 h-1 under sunlight irradiation and produces freshwater with Hg2+ under the WHO drinking water standard at 0.001 mg L-1. These results not only assist in avoiding the biodeposition effect of mercury in water but also provide an environment-friendly strategy to recycle hazardous adsorbents for water purification.


Assuntos
Água Potável , Mercúrio , Metais Pesados , Energia Solar , Purificação da Água , Humanos , Molibdênio , Luz Solar , Purificação da Água/métodos
18.
Environ Res ; 211: 113007, 2022 08.
Artigo em Inglês | MEDLINE | ID: mdl-35227673

RESUMO

The maximum targeted capture silver from contaminated water is urgently necessary for sustainable development. Herein, the perfluorination conjugated microporous polymer adsorbent (F-CMP) has been fabricated by Sonogashira-Hagihara coupling reaction and employed to remove Ag(I) ions. Characterizations of NMR, XPS and FT-IR indicate the successful synthesis of F-CMP adsorbent. The influence factors of F-CMP on Ag(I) adsorption behavior are studied, and the adsorption capacity of Ag(I) reaches 251.3 mg/g. The experimental results of isothermal adsorption and kinetic adsorption are consistent with the Freundlich model and pseudo-second-order isothermal adsorption model, which follows a multilayer adsorption behavior on the uniform surface of the adsorbent, and the chemical adsorption becomes the main rate-limiting step. Combined with DFT calculation, the adsorption mechanism of Ag(I) by F-CMP is elucidated. The peaks shift of sp before and after adsorption is larger than that of F1s, suggesting that the -CC- on the F-CMP becomes the dominant chelation site of Ag(I). Furthermore, F-CMP exhibits specific adsorption for Ag(I) in polymetallic complex water, with the maximum selectivity coefficient of 31.5. Our study may provide a new possibility of perfluorinated CMPs for effective capture of Ag(I) ions to address environmental issues.


Assuntos
Polímeros , Poluentes Químicos da Água , Adsorção , Íons , Cinética , Polímeros/química , Espectroscopia de Infravermelho com Transformada de Fourier , Água/química , Poluentes Químicos da Água/química
19.
Environ Res ; 214(Pt 3): 114076, 2022 11.
Artigo em Inglês | MEDLINE | ID: mdl-35970376

RESUMO

Low C/N municipal wastewater is difficult to be treated effectively via traditional biological methods, leading to concentrations of pollutants in effluent far exceeding increasingly strict standards. In this work, we propose a novel microalgae-bacteria tandem-type process to simultaneously remove ammonia nitrogen (NH4+-N) and phosphorus (P) from municipal wastewater. A 4.5 L microalgae-bacteria tandem-type reactor was constructed and operated stably for 40 days. The removal efficiencies of NH4+-N and P reached 97.5% and 92.9%, respectively, effluent concentrations were 0.53 and 0.17 mg/L on average, which met the Environmental quality standards for surface water in China (GB 3838-2002). Remarkably, microalgae ponds accounted for 69.3% and 76.3% of the overall NH4+-N and P removal via microalgae assimilation. Furthermore, 16 S rRNA gene amplicon sequencing revealed the abundance of bacteria changed, suggesting that the presence of microalgae leads to some species extinction and low-abundance bacteria increase. This work demonstrated that the microalgae-bacteria tandem-type processes can be efficient and widely applied in the advanced treatment of municipal wastewater.


Assuntos
Microalgas , Fósforo , Amônia , Bactérias/genética , Biomassa , Nitrogênio/análise , Lagoas , Águas Residuárias/microbiologia
20.
Environ Res ; 214(Pt 3): 113969, 2022 11.
Artigo em Inglês | MEDLINE | ID: mdl-35948151

RESUMO

Supported-adsorbents growing on the substrate in situ are equipped with the advantages of high adsorption capacity, excellent regeneration performance, and adaptability to complex wastewater. However, the effects of substrate on the adsorption properties of supported-adsorbent are rarely considered, which will hinder its development and scale-up applications. In this study, the influences of different substrates (Ti, Mo, W, CC) on the Ag+ adsorption behavior of supported-MoS2 adsorbents were investigated. The adsorption kinetics, adsorption mechanism, and the renewability of these supported-MoS2 were compared orderly. As a result, MoS2 grown on a tungsten substrate (MoS2-W) exhibits a remarkable adsorption capacity for Ag+ (1.98 mg cm-2 and 598.80 mg g-1), which is 6.38-33 times more than the other three supported-MoS2. Moreover, the MoS2-W also possesses an ultrahigh distribution coefficient (24.80 mL cm-2) for Ag+, and the selection coefficient can reach 1984. XRD and electrochemical characterization analysis indicated that Ag+ adsorption performance of supported-MoS2 is positively correlated with the degree of its amorphous structure. Substrate W with the terrific electrical properties which may facilitate the disordered growth of MoS2, resulting in more active sites exposed, and endow MoS2-W with outstanding Ag+ capture performance. Finally, the supported-MoS2 retains a high removal efficiency of Ag+ after 5 cycles of adsorption and desorption. This study provides a novel perspective for promoting the practical application of supported-sorbents to recycle heavy metals.


Assuntos
Metais Pesados , Poluentes Químicos da Água , Adsorção , Cinética , Metais Pesados/análise , Molibdênio/química , Águas Residuárias/química , Poluentes Químicos da Água/análise
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA