scholarly journals The green, ultrafine cellulose-based porous nanofibrous membranes for efficient heavy metal ion removal through incorporation of chitosan by various electrospinning ways

2022 ◽  
Author(s):  
Qiushi Li ◽  
Ganmao Su ◽  
Ronggang Luo ◽  
Guanben Du ◽  
Linkun Xie ◽  
...  
Keyword(s):  
Heavy Metal ◽  
Active Sites ◽  
Metal Removal ◽  
Copper Ions ◽  
Core Shell ◽  
Adsorption Effect ◽  
Adsorption Sites ◽  
Adsorption Performance ◽  
The Core ◽  
Nanofibrous Membranes

Abstract The rapid global industrialization worsens the contamination of heavy metals in aquatic ecosystems on the earth. In this study, the green, ultrafine cellulose-based porous nanofibrous membranes for efficient heavy metal removal through incorporation of chitosan by the conventional and core-shell electrospinning ways were firstly obtained. The relations among parameters of electrospun solution, micro-morphology and porosity for nanofibers, the variation of chemical active sites and adsorption performance of biocomposite nanofibrous membranes for conventional and core-shell electrospinning as well as the adsorption effect factors of copper ions including initial concentration, pH of solution and interaction time were comprehensively investigated. The results show that the average diameter for conventional and core-shell ultrafine nanofibers at 50% chitosan and 30% chitosan loading can achieve 56.22 nm and 37.28 nm, respectively. The core-shell cellulose acetate/chitosan (CA/CS) biocomposite nanofibrous membranes induced the surface aggregation of copper ions to impede the further adsorption. The more uniform distribution for chemical adsorption sites can be obtained by the conventional single-nozzle electrospinning than by the core-shell one, which promotes the adsorption performance of copper ions and decreases the surface shrinkage of nanofibrous membranes during adsorption. The 30% CS conventional nanofibrous membranes at the pH=5 aqueous solution showed the optimum adsorption capacity of copper ions (86.4 mg/g). The smart combination of renewable biomass with effective chemical adsorptive sites, the electrospinning technology with interwoven porous structure and the adsorption method with low cost and facile operation shows a promising prospect for water treatment.

scholarly journals Morphological and Elemental Investigations on Co–Fe–B–O Thin Films Deposited by Pulsed Laser Deposition for Alkaline Water Oxidation: Charge Exchange Efficiency as the Prevailing Factor in Comparison with the Adsorption Process

2021 ◽  
Author(s):  
Y. Popat ◽  
M. Orlandi ◽  
S. Gupta ◽  
N. Bazzanella ◽  
S. Pillai ◽  
...  
Keyword(s):  
Pulsed Laser Deposition ◽  
Water Oxidation ◽  
Active Sites ◽  
High Surface ◽  
Pulsed Laser ◽  
Industrial Applications ◽  
Active Species ◽  
Laser Deposition ◽  
Core Shell ◽  
Adsorption Sites

Abstract Mixed transition-metals oxide electrocatalysts have shown huge potential for electrochemical water oxidation due to their earth abundance, low cost and excellent electrocatalytic activity. Here we present Co–Fe–B–O coatings as oxygen evolution catalyst synthesized by Pulsed Laser Deposition (PLD) which provided flexibility to investigate the effect of morphology and structural transformation on the catalytic activity. As an unusual behaviour, nanomorphology of 3D-urchin-like particles assembled with crystallized CoFe2O4 nanowires, acquiring high surface area, displayed inferior performance as compared to core–shell particles with partially crystalline shell containing boron. The best electrochemical activity towards water oxidation in alkaline medium with an overpotential of 315 mV at 10 mA/cm2 along with a Tafel slope of 31.5 mV/dec was recorded with core–shell particle morphology. Systematic comparison with control samples highlighted the role of all the elements, with Co being the active element, boron prevents the complete oxidation of Co to form Co3+ active species (CoOOH), while Fe assists in reducing Co3+ to Co2+ so that these species are regenerated in the successive cycles. Thorough observation of results also indicates that the activity of the active sites play a dominating role in determining the performance of the electrocatalyst over the number of adsorption sites. The synthesized Co–Fe–B–O coatings displayed good stability and recyclability thereby showcasing potential for industrial applications. Graphic Abstract

scholarly journals Preparation of Carbon Aerogel Electrode for Electrosorption of Copper Ions in Aqueous Solution

Materials ◽  
2019 ◽  
Vol 12 (11) ◽  
pp. 1864 ◽  
Author(s):  
Ziling Cao ◽  
Chen Zhang ◽  
Zhuoxin Yang ◽  
Qing Qin ◽  
Zhihua Zhang ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Heavy Metal ◽  
Copper Ions ◽  
Sol Gel ◽  
Copper Ion ◽  
Carbon Aerogel ◽  
Double Layers ◽  
Molar Ratio ◽  
Adsorption Effect ◽  
Control Variate

Carbon aerogel (CA) has a rich porous structure, in which micropores and mesopores provide a huge specific surface area to form electric double layers. This property can be applied to the application of capacitive deionization (CDI). The adsorption effect of CA electrode on Cu2+ in an aqueous solution was explored for solving heavy metal water pollution. The CAs were synthesized by a sol-gel process using an atmospheric drying method. The structure of CAs was characterized by scanning in an electron microscope (SEM) and nitrogen adsorption/desorption techniques. The adsorption system was built using Cu2+ solution as the simulation of heavy metal pollution solution. The control variate method was used to investigate the effect of the anion species in copper solution, the molar ratio of resorcinol to catalyst (R/C) of CA, and the applied voltage and concentration of copper ion on the adsorption results.

scholarly journals Properties of Cobalt- and Nickel-Doped Zif-8 Framework Materials and Their Application in Heavy-Metal Removal from Wastewater

Nanomaterials ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1636
Author(s):  
Bowen Shen ◽  
Bixuan Wang ◽  
Liying Zhu ◽  
Ling Jiang
Keyword(s):  
Heavy Metal ◽  
Metal Removal ◽  
Copper Ions ◽  
Heavy Metal Removal ◽  
Nickel Ions ◽  
Cobalt Ions ◽  
Framework Materials ◽  
Metal Treatment ◽  
Dichromate Ions ◽  
Cobalt And Nickel

Heterometallic zeolite imidazole framework materials (ZIF) exhibit highly attractive properties and have drawn increased attention. In this study, a petal-like zinc based ZIF-8 crystal and materials doped with cobalt and nickel ions were efficiently prepared in an aqueous solution at room temperature. It was observed that doped cobalt and nickel had obviously different effects on the morphology of ZIF-8. Cobalt ions were beneficial for the formation of ZIF-8, while addition of nickel ions tended to destroy the original configuration. Then we compared the absorption ability for metal ions between petal-like ZIF-8 and its doped derivatives with anion dichromate ions (Cr2O72−) and cation copper ions (Cu2+) as the absorbates. Results indicated that saturated adsorption capacities of Co@ZIF-8 and Ni@ZIF-8 for Cr2O72− reach 43.00 and 51.60 mg/g, while they are 1191.67 and 1066.67 mg/g for Cu2+, respectively, which are much higher than the original ZIF-8 materials. Furthermore, both the heterometallic ZIF-8 materials show fast adsorption kinetics to reach adsorption equilibrium. Therefore, petal-like ZIF-8 with doped ions can be produced through a facile method and can be an excellent candidate for further applications in heavy-metal treatment.

scholarly journals Silica Coating of Metal-Loaded H-ZSM-22 to Form the Core-Shell Nanostructures: Characterization, Textural Properties, and Catalytic Potency in the Esterification of Oleic Acid

2021 ◽  
Vol 2021 ◽  
pp. 1-16
Author(s):  
Maryam Haghighi ◽  
Mehranoosh Fereidooni
Keyword(s):  
Oleic Acid ◽  
Electron Microscope ◽  
Active Sites ◽  
Maximum Yield ◽  
Operating Conditions ◽  
Molar Ratio ◽  
Emission Spectrometry ◽  
Esterification Reaction ◽  
Core Shell ◽  
The Core

In this study, ZSM-22 was synthesized using N,N-diethylaniline as a template through a hydrothermal method. The proton and various metals such as zirconium, strontium, and iron were immobilized on the surface of obtained zeolites through the ion exchange method. The catalysts were studied by Fourier-Transform Infrared Spectroscopy (FT-IR), X-Ray Diffraction (XRD), Brunauer–Emmett–Teller (BET) adsorption isotherms, Transmission Electron Microscope (TEM), Scanning Electron Microscope (SEM), Inductively Coupled Plasma-Optical Emission Spectrometry (ICP-OES) elemental analysis, and Temperature-Programmed Desorption of ammonia (TPD-NH3) technique for determining the number of acid sites. In the esterification reaction of oleic acid, the operating conditions such as catalyst dosage, temperature, molar ratio of methanol to oil, and reaction time were optimized and adjusted at 11 wt%, 70°C, 10 : 1, and 48 h subsequently. The maximum yield% of 48.07% was achieved in the presence of Zr-H-ZSM-22 at optimum conditions. In order to improve the efficiency of three zeolites Zr-H-ZSM-22, Fe-H-ZSM-22, and Sr-H-ZSM-22, the core-shell structures with SiO2 coating were prepared. Zr-H-ZSM-22@SiO2 was less active than Zr-H-ZSM-22 due to the SiO2 coverage of Lewis active sites.

scholarly journals The Auxiliary Effect of Copper Ions on the Depressant Effect of Sodium Thioglycolate in Chalcopyrite Flotation

Minerals ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 157
Author(s):  
Chonghui Zhang ◽  
Tingshu He ◽  
Wei Chen ◽  
Xianzhong Bu ◽  
Sen Wang ◽  
...  
Keyword(s):  
Zeta Potential ◽  
Photoelectron Spectroscopy ◽  
Active Sites ◽  
Copper Ions ◽  
Depressant Effect ◽  
X Ray ◽  
Adsorption Sites ◽  
Effect Of Copper ◽  
Adsorption Layers ◽  
Hydrophobic Substance

Sodium thioglycolate is a chalcopyrite depressant, but its depressant effect is weak. The paper investigated the effect of CuSO4 on the depressant performance of sodium thioglycolate towards chalcopyrite through flotation tests, Zeta potential measurements, X-ray photoelectron spectroscopy (XPS) analyses and Fourier-transform infrared (FTIR) spectra measurements. It was found that copper ions could improve the depressant effect of sodium thioglycolate on chalcopyrite. The results showed that copper ions could adsorb on the surface of chalcopyrite and form mixed copper sulfide and cupric oxides/hydroxides adsorption layers. As a result, the mineral composition on the chalcopyrite surface was changed. With sodium thioglycolate treatment, the Zeta potential and the adsorption sites of chalcopyrite surface were both increased, and the hydrophobic substance Sn2−/S0 concentration was decreased. The electrostatic repulsion of chalcopyrite surface with sodium thioglycolate was also decreased, which made the sodium thioglycolate interact with chalcopyrite more easily. The more active sites could adsorb more sodium thioglycolate, which improved the hydrophilia of chalcopyrite. At the same time, the decrease of Sn2−/S0 concentration could further improve the hydrophilia of chalcopyrite. The results show that the copper ions could exhibit auxiliary effect with sodium thioglycolate and could further enhance the depressant effect of sodium thioglycolate on the chalcopyrite flotation. This paper provides new insights into the depression of chalcopyrite flotation by sodium thioglycolate.

scholarly journals Preparation of Monoclinic Pyrrhotite by Thermal Decomposition of Jarosite Residues and Its Heavy Metal Removal Performance

Minerals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 267
Author(s):  
Cuimin Xu ◽  
Qiaoqin Xie ◽  
Fan Xu ◽  
Yuefei Zhou ◽  
Hanlin Wang ◽  
...  
Keyword(s):  
Heavy Metal ◽  
Reaction Temperature ◽  
Photoelectron Spectroscopy ◽  
Metal Removal ◽  
Formation Rate ◽  
Heavy Metal Removal ◽  
Phase Evolution ◽  
The Core ◽  
Hydrometallurgical Processing ◽  
Monoclinic Pyrrhotite

Jarosite residues produced by zinc hydrometallurgical processing are hazardous solid wastes. In this study, monoclinic pyrrhotite (M­Po) was prepared by the pyrolysis of jarosite residues in H2S atmosphere. The influence of gas speed, reaction temperature, and time was considered. The mineral phase, microstructure, and elemental valence of the solids before and after pyrolysis were analyzed using X­ray diffraction, scanning electron microscopy, and X­ray photoelectron spectroscopy, respectively. The performances of the prepared M­Po on the removal of Zn and Pb from aqueous solution were evaluated. The results show M­Po to be the sole product at the reaction temperatures of 550 to 575 °C. Most of the M­Po particles are at the nanometer scale and display xenomorphic morphology. The phase evolution process during pyrolysis is suggested as jarosite → hematite/magnetite → pyrite → pyrite+M­Po → M­Po+hexagonal pyrrhotite (H­Po) → H­Po. The formation rate, crystallinity, and surface microtexture of M­Po are controlled by reaction temperature and time. Incomplete sulfidation may produce coarse particles with core–shell (where the core is oxide and the shell is sulfide) and triple-layer (where the core is sulfate, the interlayer is oxide, and the shell is sulfide) structures. M­Po produced at 575 °C exhibits an excellent heavy metal removal ability, which has adsorption capacities of 25 mg/g for Zn and 100 mg/g for Pb at 25 °C and pH ranges from 5 to 6. This study indicates that high-temperature sulfidation is a novel and efficient method for the treatment and utilization of jarosite residues.

Free-standing SiO2/TiO2–MoS2 composite nanofibrous membranes as nanoadsorbents for efficient Pb(ii) removal

2020 ◽  
Vol 44 (30) ◽  
pp. 13030-13035 ◽  
Author(s):  
Luiza A. Mercante ◽  
Rafaela S. Andre ◽  
Rodrigo Schneider ◽  
Luiz H. C. Mattoso ◽  
Daniel S. Correa
Keyword(s):  
Heavy Metal ◽  
Hybrid Material ◽  
Metal Removal ◽  
Heavy Metal Removal ◽  
Free Standing ◽  
Practical Utility ◽  
Nanofibrous Membranes ◽  
Ceramic Nanofibers

The practical utility of a hybrid material based on flexible free-standing ceramic nanofibers functionalized with MoS2 for heavy metal removal.

scholarly journals Filler-Modified Castor Oil-Based Polyurethane Foam for the Removal of Aqueous Heavy Metals Detected Using Laser-Induced Breakdown Spectroscopy (LIBS) Technique

Polymers ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 903 ◽  
Author(s):  
M. Iqhrammullah ◽  
Marlina ◽  
R. Hedwig ◽  
I. Karnadi ◽  
K. H. Kurniawan ◽  
...  
Keyword(s):  
Heavy Metal ◽  
Polyurethane Foam ◽  
Castor Oil ◽  
Heavy Metal Ions ◽  
Metal Removal ◽  
Heavy Metal Removal ◽  
Laser Induced Breakdown Spectroscopy ◽  
Breakdown Spectroscopy ◽  
Adsorption Performance ◽  
Laser Induced Breakdown

The use of polymeric material in heavy metal removal from wastewater is trending. Heavy metal removal from wastewater of the industrial process is of utmost importance in green/sustainable manufacturing. Production of absorbent materials from a natural source for industrial wastewater has been on the increase. In this research, polyurethane foam (PUF), an adsorbent used by industries to adsorb heavy metal from wastewater, was prepared from a renewable source. Castor oil-based polyurethane foam (COPUF) was produced and modified for improved adsorption performance using fillers, analyzed with laser-induced breakdown spectroscopy (LIBS). The fillers (zeolite, bentonite, and activated carbon) were added to the COPUF matrix allowing the modification on its surface morphology and charge. The materials were characterized using Fourier-transform infrared (FTIR), scanning electron microscopy (SEM), and thermal gravimetry analysis (TGA), while their adsorption performance was studied by comparing the LIBS spectra. The bentonite-modified COPUF (B/COPUF) gave the highest value of the normalized Pb I (405.7 nm) line intensity (2.3), followed by zeolite-modified COPUF (Z/COPUF) (1.9), and activated carbon-modified COPUF (AC/COPUF) (0.2), which indicates the adsorption performance of Pb2+ on the respective materials. The heavy metal ions’ adsorption on the B/COPUF dominantly resulted from the electrostatic attraction. This study demonstrated the potential use of B/COPUF in adsorption and LIBS quantitative analysis of aqueous heavy metal ions.

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