Design of simple and efficient metal nanoparticles templated on ZnO-chitosan coated textile cotton towards the catalytic reduction of organic pollutants

In this study simple, facile and highly active silver coated ZnO-chitosan (Ag/ZnO-CH) textile cotton supported nanocomposites were developed. The nanocomposites were characterized by UV-visible spectroscopy, scanning electron microscopy (SEM), energy dispersive X-rays spectroscopy (EDX), fourier transform infrared spectroscopy (FTIR) and X-rays diffraction (XRD). The prepared nanocomposite fibers were used for the selective removal of seven model pollutants, including para-nitrophenol (p-NP), meta-nitrophenol (m-NP), ortho-nitrophenol (o-NP), 2,4,6-trinitrophenol (TNP), and dyes of methyl orange (MO), congo red (CR), and methyl red (MR). The apparent rate constant (Kapp) of pseudo first order kinetic for p-NP was 2.813 × 10−3 s−1 and 1.663 × 10−3 s−1 for MO dye. Among the different nitroarenes, the reaction rate matched the ordered of p-NP >TNP > m-NP > o-NP, while for the dyes it was MO > CR > MR. Ag/ZnO-CH nanocomposites were recycled multiple times without any significant loss of its catalytic activity. The higher stability of the Ag/ZnO-CH nanofibers also allows the catalyst to be separated easily by just pulling the catalyst from the reaction mixture and reused. The clean and facile, simple synthesis procedure, outstanding properties and low-cost supports allow these catalysts to be used in the reduction of the organic pollutants individually as well as collectively in the mixture of dyes in wastewater at room temperature.

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Highly efficient and simultaneous catalytic reduction of multiple toxic dyes and nitrophenols waste water using highly active bimetallic PdO–NiO nanocomposite

Scientific Reports ◽

10.1038/s41598-021-01989-7 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

A. G. Ramu ◽

Dongjin Choi

Keyword(s):

Rate Constant ◽

Catalytic Reduction ◽

Low Cost ◽

Reduction Rate ◽

Aquatic Organism ◽

Significant Loss ◽

Azo Compounds ◽

Highly Active ◽

High Efficient ◽

High Reduction

AbstractAzo dyes and nitrophenols have been widely used in the various industry which are highly toxic and affecting the photosynthetic cycle of aquatic organism. The industry disposals increase the accumulation of azo compounds in the environment. In the present study, we synthesized the low cost, PdO-doped NiO hetero-mixture via simple hydrothermal combined calcination process. The morphology results proved that, the spherical PdO nanoparticles are evenly doped with NiO nanoparticles. The band gap values of metal oxides NiO, PdO and PdO–NiO composite were found to be 4.05 eV, 3.84 eV and 4.24 eV, respectively. The high optical bandgap (Eg) value for composite suggests that the PdO interface and NiO interface are closely combined in the composite. The catalytic activity of the PdO–NiO was analyzed for the reduction of different toxic azo compounds namely, 4-nitrophenol (NP), 2,4-dinitrophenol (DNP), 2,4,6-trinitrophenol (TNP), methylene blue (MB), rhodamine B (RhB) and methyl orange (MO) separately and their mixture with the presence of a NaBH4. For the first time, the large volume of the toxic azo compounds was reduced into non-toxic compounds with high reduction rate. The proposed PdO–NiO catalyst exhibit excellent rate constant 0.1667, 0.0997, 0.0686 min−1 for NP, DNP and TNT and 0.099, 0.0416 and 0.0896 min−1 for MB, RhB and MO dyes respectively which is higher rate constant than the previously reported catalysts. Mainly, PdO–NiO completes the reduction of mixture of azo compounds within 8 min. Further, PdO–NiO exhibit stable reduction rate of azo compounds over five cycles with no significant loss. Hence, the proposed low cost and high efficient PdO–NiO catalyst could be the promising catalyst for degradation of azo compounds.

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High Selectivity and Reusability of Biomass-Based Adsorbent for Chloramphenicol Removal

Nanomaterials ◽

10.3390/nano11112950 ◽

2021 ◽

Vol 11 (11) ◽

pp. 2950

Author(s):

Weinan Xing ◽

Qi Liu ◽

Jingyi Wang ◽

Siye Xia ◽

Li Ma ◽

...

Keyword(s):

Adsorption Capacity ◽

Solution Structure ◽

Low Cost ◽

Water Environment ◽

Significant Loss ◽

Order Kinetic ◽

Solution Ph ◽

Suitable Material ◽

Order Kinetic Model ◽

Pseudo Second Order

Recently, biomass-based materials have attracted increasing attention because of their advantages of low cost, environment-friendly and nonpollution. Herein, the feasibility of using corn stalk biomass fiber (CF) and Fe3O4 embedded chitosan (CS) as a novel biomass-based adsorbent (CFS) to remove chloramphenicol (CAPC) from aqueous solution. Structure of CFS was characterized by using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Brunauer–Emmett–Teller (BET), scanning electron microscopy (SEM) and zeta potential techniques. The effects of solution pH, adsorption time and ion strength on the adsorption capacity were examined. Adsorption isotherms obtained from batch experiments were better fitted by Langmuir model compared with Freundlich model, Dubinin–Radushkevich model and Temkin model. Adsorption kinetic data matched well to the pseudo-second order kinetic model. CAPC adsorption was endothermic, spontaneous, and entropy-increasing nature on CFS. In addition, the CFS could be separated by an external magnetic field, recycled, and reused without any significant loss in the adsorption capacity of CAPC. Based on these excellent performances, there is potential that CFS can be considered as a proficient and economically suitable material for the CAPC removal from the water environment.

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Crystal structures of hybrid completely reduced phosphomolybdates and catalytic performance applied as molecular catalysts for the reduction of chromium(VI)

Acta Crystallographica Section C Structural Chemistry ◽

10.1107/s2053229618013025 ◽

2018 ◽

Vol 74 (11) ◽

pp. 1310-1324 ◽

Cited By ~ 3

Author(s):

Xuerui Tian ◽

Xing Xin ◽

Yuanzhe Gao ◽

Dandan Dai ◽

Jinjin Huang ◽

...

Keyword(s):

Environmental Remediation ◽

Catalytic Reduction ◽

Noncovalent Interactions ◽

Low Cost ◽

Catalytic Performance ◽

Vital Role ◽

Chromium Vi ◽

Highly Active ◽

Supramolecular Networks ◽

Molecular Catalysts

The exploration of highly efficient and low-cost catalysts for the treatment of hexavalent chromium CrVI in environmental remediation is currently one of the most challenging topics. Here, three phosphomolybdate hybrid compounds have been successfully isolated by the hydrothermal method and been applied as supramolecular catalysts for the reduction of CrVI. Single-crystal X-ray diffraction revealed their formulae as (H2bpp)2[Fe(H2O)][Sr(H2O)4]2{Fe[Mo6O12(OH)3(H2PO4)(HPO4)(PO4)2]2}·5H2O (1), (H2bpp)2[Na(H2O)(OC2H5)][Fe(H2O)2][Ca(H2O)2]2{Fe[Mo6O12(OH)3(H2PO4)(HPO4)(PO4)2]2}·4H2O (2) and (H2bpe)3{Fe[Mo6O12(OH)3(HPO4)3(H2PO4)]2}·8H2O (3) [bpp is 1,3-bis(pyridin-4-yl)propane (C13H14N2) and bpe is trans-1,2-bis(pyridin-4-yl)ethylene (C12H10N2)]. The three hybrids consist of supramolecular networks built up by noncovalent interactions between {Fe[P4Mo6 VO31]2}22− polyanions and protonated organic cations. This kind of hybrid polyoxometalate could be applied as heterogeneous molecular catalysts for the reduction of CrVI. It was found that the organic moiety plays a vital role in influencing the catalytic activity of the polyanions. Organic bpp-containing hybrids 1 and 2 are highly active in the catalytic reduction of heavy metal CrVI ions using HCOOH as reductant, while bpe-containing hybrid 3 is inactive to this reaction. This work is significant for the design of new catalysts, as well as the exploration of reaction mechanisms at a molecular level.

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Synthesizing CuO/CeO2/ZnO Ternary Nano-Photocatalyst with Highly Effective Utilization of Photo-Excited Carriers under Sunlight

Nanomaterials ◽

10.3390/nano10101946 ◽

2020 ◽

Vol 10 (10) ◽

pp. 1946 ◽

Cited By ~ 1

Author(s):

Kaiyi Luo ◽

Jing Li ◽

Wenyu Hu ◽

Han Li ◽

Qiuping Zhang ◽

...

Keyword(s):

Band Structure ◽

Visible Light ◽

Uv Light ◽

Low Cost ◽

Sol Gel ◽

Active Species ◽

Order Kinetic ◽

Highly Efficient ◽

Dye Decomposition ◽

Highly Active

The construction of heterostructured photocatalyst with an appropriate energy band structure will help realize highly efficient photo-excited charge separation. In this study, ternary CuO/CeO2/ZnO nano-particle (NP) composites were synthesized by a facile two-step sol-gel method, which exhibit significantly enhanced photocatalytic degradation performance for various organic pollutants under UV and visible light excitation. The photo-responses to both UV and visible light, as well as the visible light absorption and utilization rates of ZnO are found to be synergistically intensified by CeO2 and CuO co-coupling. The first-order kinetic constants (K) of 3%CuO/CeO2/ZnO for methylene blue (MB) degradation are ~3.9, ~4.1 and ~4.8 times higher than ZnO under UV light, visible light and simulated sunlight illumination, respectively. The roles of CuO and CeO2 in optical properties and photo-degradation under UV and visible light were explored. Besides, the photogenic holes (h+) of ZnO, CeO2, and the produced hydroxyl radicals (·OH) are proved to be the main active species under UV light. Dissimilarly, under visible light, the superoxide radicals (·O2−) formed by the reactions between oxygen molecules and the photo-generated electrons (e−) of CuO moving towards the catalysts surface are also found to be important for promoting dye decomposition. The improved photo-responses, the well-matched band structure that facilitates charge transfer processes, and the highly efficient utilization of the photo-excited carriers of the ternary nano-heterostructure are suggested to be the key factors for the remarkable enhancement of photocatalytic performance of ZnO nano-photocatalyst. This work offers a low-cost strategy to acquire highly active UV and visible light-driven photocatalyst.

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Surface interaction of sweet potato peels (Ipomoea batata) with Cd(II) and Pb(II) ions in aqueous medium

10.31221/osf.io/gfdht ◽

2019 ◽

Author(s):

Chem Int

Keyword(s):

Aqueous Medium ◽

Sweet Potato ◽

Adsorption Process ◽

Low Cost ◽

Correlation Coefficients ◽

Order Kinetic ◽

Thermodynamic Evaluation ◽

Dissociative Mechanism ◽

Pseudo Second Order ◽

Potato Peels

The removal of Cd(II) and Pb(II) ions from aqueous medium was studied using potato peels biomass. The adsorption process was evaluated using Atomic Absorption Spectrophotometer (AAS). The Vibrational band of the potato peels was studied using Fourier Transform Infrared Spectroscopy (FTIR). The adsorption process was carried out with respect to concentration, time, pH, particle size and the thermodynamic evaluation of the process was carried at temperatures of 30, 40, 50 and 60(0C), respectively. The FTIR studies revealed that the potato peels was composed of –OH, -NH, –C=N, –C=C and –C-O-C functional groups. The optimum removal was obtained at pH 8 and contact time of 20 min. The adsorption process followed Freundlich adsorption and pseudo second-order kinetic models with correlation coefficients (R2) greater than 0.900. The equilibrium adsorption capacity showed that Pb(II) ion was more adsorbed on the surface of the potato peels biomass versus Cd (II) ion (200.91 mg/g > 125.00 mg/g). The thermodynamic studies indicated endothermic, dissociative mechanism and spontaneous adsorption process. This study shows that sweet potato peels is useful as a low-cost adsorbent for the removal of Cd(II) and Pb(II) ions from aqueous medium.

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Modelling of bacterial removal in wastewater storage reservoir for irrigation purposes: a case study in Sicily, Italy

Water Science & Technology Water Supply ◽

10.2166/ws.2003.0059 ◽

2003 ◽

Vol 3 (4) ◽

pp. 169-175 ◽

Cited By ~ 2

Author(s):

S. Barbagallo ◽

F. Brissaud ◽

G.L. Cirelli ◽

S. Consoli ◽

P. Xu

Keyword(s):

Municipal Wastewater ◽

High Reliability ◽

Low Cost ◽

Public Awareness ◽

Storage System ◽

Wastewater Reuse ◽

Order Kinetic ◽

Aquifer Recharge ◽

Mediterranean Countries ◽

Storage Reservoirs

In arid and semiarid regions the reclamation and reuse of municipal wastewater can play a strategic role in alleviating water resources shortages. Public awareness is growing about the need to recycle and reuse water for increasing supply availability. Many wastewater reuse projects have been put in operation in European and Mediterranean countries adopting extensive treatment systems such as aquifer recharge, lagooning, constructed wetlands, and storage reservoirs, mainly for landscape and agricultural irrigation. In agricultural reuse systems, there is an increasing interest in extensive technologies because of their high reliability, and easy and low cost operation and maintenance. Wastewater storage reservoirs have become the option selected in many countries because of the advantages they present in comparison with other treatment alternatives, namely the coupling of two purposes, stabilization and seasonal regulation. This paper describes an example of a wastewater storage system, built in Caltagirone (Sicily, Italy). The storage results in a tertiary treatment of a continuous inlet flow of activated sludge effluents. The prediction of the microbiological water quality has been evaluated by means of a non-steady-state first-order kinetic model. Single and multiple regressions were applied to determine the main variables that most significantly affected die-off coefficients. The proposed model has been calibrated using the results of a field monitoring carried out during a period from March to October 2000.

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Comparison of the fixation of several metal ions onto a low-cost biopolymer

Water Science & Technology Water Supply ◽

10.2166/ws.2002.0172 ◽

2002 ◽

Vol 2 (5-6) ◽

pp. 217-224 ◽

Cited By ~ 6

Author(s):

Z. Reddad ◽

C. Gérente ◽

Y. Andrès ◽

P. Le Cloirec

Keyword(s):

Aqueous Solutions ◽

Metal Ions ◽

Low Cost ◽

Operating Conditions ◽

Order Kinetic ◽

Adsorption Mechanisms ◽

Equilibrium Data ◽

Order Kinetic Model ◽

Beet Pulp ◽

Removal Of Metal Ions

In the present work, sugar beet pulp, a common waste from the sugar refining industry, was studied in the removal of metal ions from aqueous solutions. The ability of this cheap biopolymer to sorb several metals namely Pb2+, Cu2+, Zn2+, Cd2+ and Ni2+ in aqueous solutions was investigated. The metal fixation capacities of the sorbent were determined according to operating conditions and the fixation mechanisms were identified. The biopolymer has shown high elimination rates and interesting metal fixation capacities. A pseudo-second-order kinetic model was tested to investigate the adsorption mechanisms. The kinetic parameters of the model were calculated and discussed. For 8 × 10-4 M initial metal concentration, the initial sorption rates (v0) ranged from 0.063 mmol.g-1.min-1 for Pb2+ to 0.275 mmol.g-1.min-1 for Ni2+ ions, with the order: Ni2+ > Cd2+ > Zn2+ > Cu2+ > Pb2+. The equilibrium data fitted well with the Langmuir model and showed the following affinity order of the material: Pb2+ > Cu2+ > Zn2+ > Cd2+ > Ni2+. Then, the kinetic and equilibrium parameters calculated qm and v0 were tentatively correlated to the properties of the metals. Finally, equilibrium experiments in multimetallic systems were performed to study the competition of the fixation of Pb2+, Zn2+ and Ni2+ cations. In all cases, the metal fixation onto the biopolymer was found to be favourable in multicomponent systems. Based on these results, it is demonstrated that this biosorbent represents a low-cost solution for the treatment of metal-polluted wastewaters.

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Chemical Modification of Combusted Coal Gangue for U(VI) Adsorption: Towards a Waste Control by Waste Strategy

Sustainability ◽

10.3390/su13158421 ◽

2021 ◽

Vol 13 (15) ◽

pp. 8421

Author(s):

Yuan Gao ◽

Jiandong Huang ◽

Meng Li ◽

Zhongran Dai ◽

Rongli Jiang ◽

...

Keyword(s):

Structural Analysis ◽

High Efficiency ◽

Low Cost ◽

Chemical Activation ◽

Cost Effective ◽

Coal Gangue ◽

Order Kinetic ◽

Practical Applications ◽

Detailed Structural Analysis ◽

Alkaline Conditions

Uranium mining waste causes serious radiation-related health and environmental problems. This has encouraged efforts toward U(VI) removal with low cost and high efficiency. Typical uranium adsorbents, such as polymers, geopolymers, zeolites, and MOFs, and their associated high costs limit their practical applications. In this regard, this work found that the natural combusted coal gangue (CCG) could be a potential precursor of cheap sorbents to eliminate U(VI). The removal efficiency was modulated by chemical activation under acid and alkaline conditions, obtaining HCG (CCG activated with HCl) and KCG (CCG activated with KOH), respectively. The detailed structural analysis uncovered that those natural mineral substances, including quartz and kaolinite, were the main components in CCG and HCG. One of the key findings was that kalsilite formed in KCG under a mild synthetic condition can conspicuous enhance the affinity towards U(VI). The best equilibrium adsorption capacity with KCG was observed to be 140 mg/g under pH 6 within 120 min, following a pseudo-second-order kinetic model. To understand the improved adsorption performance, an adsorption mechanism was proposed by evaluating the pH of uranyl solutions, adsorbent dosage, as well as contact time. Combining with the structural analysis, this revealed that the uranyl adsorption process was mainly governed by chemisorption. This study gave rise to a utilization approach for CCG to obtain cost-effective adsorbents and paved a novel way towards eliminating uranium by a waste control by waste strategy.

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