N2 Adsorption-desorption Isotherm Analysis Research Articles

Effect of polypyrrole-derived N-doped carbon coating on the sodium storage properties of NiCo2S4 synthesized by recycling discarded mobile phone batteries

NiCo2S4 with a spherical spinel structure was innovatively synthesized from discarded mobile phone batteries using a simple hydrothermal method, and the surface was coated with N-doped carbon to form NiCo2S4@NC. The products were used as anode materials of sodium-ion batteries to study the effect of the N-doped carbon layer on the electrochemical properties, structure and morphology. The results of XRD, FESEM and TEM revealed that the N-doped carbon layer derived by carbonizing polypyrrole had a minimal effect on the structure and morphology of NiCo2S4, but was coated on the surface of NiCo2S4 with different thicknesses to adjust the electrochemical performance. The presence of N-doped carbon in NiCo2S4@NC was confirmed by Raman spectroscopy. The mesoporous structure of NiCo2S4 and NiCo2S4@NC was corroborated by N2 adsorption-desorption isotherm analysis, and the optimal specific surface area and pore size were 23.14 cm2/g and 18.0 nm, respectively. X-ray photoelectron spectroscopy indicated that Co2+/Co3+ and Ni2+/Ni3+ coexist in the spinel NiCo2S4@NC50 synthesized upon adding 50 μL of pyrrole monomer. NiCo2S4@NC50 outperformed other products in terms of its electrochemical properties, where its initial discharge specific capacity under the current density of 0.1 A g−1 was 1099.6 mA h g−1 and the specific capacity following 100 cycles reached 327.5 mA h g−1. NiCo2S4@NC50 exhibited an optimal electrochemical performance and demonstrated a competent approach toward recycling discarded mobile phone batteries and building electrodes with high performance for use in energy equipment.

Investigating the impact of structural defects in MWCNT/MnFe2O4 nanocomposite for efficient photodegradation of cationic dye

The co-precipitation hydrothermal method was used to prepare MWCNT (0.01g and 0.04g)/MnFe2O4 composites and the valence state elemental compositions were verified with XPS. The TEM micrograph revealed that the functionalized MWCNTs were well-dispersed in the matrix and retained their tubular structure. PL analysis indicates an increase in electron-hole pair separation, electron trapping in the MWCNT and an increase in structural defects. The result of positron annihilation lifetime spectroscopy (PALS) reveals that the concentration of composite surface defect increases with CNT. Additionally, these findings show that the vacancy clusters and voids are more prominent in the interface of the MWCNT/MnFe2O4 composite compared to the MnFe2O4 particle surface. N2 adsorption-desorption isotherms analysis confirmed the surface area change in the composite. Notably, the MWCNT/MnFe2O4 composite exhibited significantly enhanced photocatalytic activity compared to pure MnFe2O4, leading to superior efficiency in the removal of methylene blue (MB).

Synthesis of novel Cu2WS4/Bi2WO6 heterojunctions and evaluation of their photocatalytic activity for removal of tetracycline under visible light irradiation

In order to change the photocatalytic performance of bismuth tungstate monomer material, the Z-type heterojunction Cu2WS4/Bi2WO6 (CWS/BW) system was formed by loading Cu2WS4 on Bismuth tungstate by hydrothermal method, and then characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). It was concluded that the crystallinity of Cu2WS4/Bi2WO6 system varied with the change of the composite ratio, and no impurity influence was found. The morphology of Cu2WS4/Bi2WO6 system reflects the flower bulbous formed by the superposition of Cu2WS4 nanosheets and Bi2WO6 nanosheets. The overall analysis shows that Cu2WS4 and Bi2WO6 were successfully compounded. Through the characterization analysis of ultraviolet–visible diffuse reflectance absorption spectra (UV–Vis DRS), photoluminescence spectrogram (PL) and N2 adsorption-desorption isotherm analysis (BET), it was concluded that the Cu2WS4/Bi2WO6 system had a higher specific surface area, a wider light corresponding range and a lower photogenerated electron-hole recombination rate.Experiments show that the 5-CWS/BW in the Cu2WS4/Bi2WO6 system had the strongest photocatalytic effect under visible light, and the light degradation rate in 100min can reach 80%, which is 1.7 times and 3.2 times that of monomer Bi2WO6 and Cu2WS4, respectively. 5-CWS/BW still had high activity under different experimental conditions. Later, cyclic experiments proved that the material had strong stability. Finally, the main active substances in photocatalysis were clarified through free radical capture experiments and electron spin resonance (ESR) technology, and the photocatalytic mechanism of Cu2WS4/Bi2WO6 system was inferred.

Building nickel tungstate nanospheres anchored polyaniline conductive matrixes for trace level electrochemical determination of theobromine in food samples

In this work, a nickel tungstate nanospheres-anchored polyaniline nanocomposite (NiWO4/PANI) was prepared by using a hydrothermal route followed by a chemical oxidative polymerization route and explored as an electrode material for the determination of theobromine (TB). The X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analysis confirm the structural-compositional details of NiWO4/PANI nanocomposite. Further, the successful fabrication of NiWO4 nanospheres perfectly anchoring on the conductive matrix of PANI is revealed by transmission electron microscope (TEM) analysis. The N2 adsorption-desorption isotherm analysis revealed the specific surface area of the composite is 28.49 m2/g. Due to the feasible multiple electroactive sites and the synergistic effect between NiWO4 and conductive PANI matrix in the NiWO4/PANI nanocomposite, it enables rapid electron migration and possesses high electrical conductivity during the sensing performances. From the amperometric i-t method, NiWO4/PANI sensor exhibits a wide linear range (0.05–1350.6 μM) and a low detection limit (0.0079 µM). Besides, NiWO4/PANI based sensor shows excellent stability, anti-interference ability and reproducibility, suggesting NiWO4/PANI composite-modified sensors could be a potential candidate for determining TB in food samples with suitable recovery ranges.

Unleashing the catalytic potency of nanoporous copper oxide particles derived from copper 5-nitroisophthalate MOF towards the multicomponent synthesis of 2,3-dihydroquinazolinones

Recent years have witnessed noteworthy advancements in the designing of MOFs and their derived materials. The present work for the very first time reports the successful fabrication of a series of CuO nanoparticles (NPs) by the controlled pyrolysis of Cu-5-nitroisophthalate (Cu-NIPA) metal organic framework (MOF) and employed it further as a catalytic entity for accessing 2,3-dihydroquinazolinone moieties. The systematically designed CuO nanoarchitectures were synthesized in a single step through pyrolysis of Cu-5-NIPA in air atmosphere and analytically affirmed using a multitude of advanced physico-chemical characterization tools such as Fourier transform infrared (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), powder X-ray diffraction (PXRD), N2 adsorption-desorption isotherm, Raman spectroscopy and X-ray photoelectron spectroscopy (XPS) analysis. The catalytic potential of the developed CuO nanoarchitectures was subsequently evaluated in the one-pot multicomponent coupling of aromatic aldehyde, isatoic anhydride, alkyl/aryl amine to produce 2,3-dihydroquinazolinone scaffolds (up to 97% yield). Furthermore, a proposed catalytic mechanism for the concerned reaction has also been provided. Some of the additional startling attributes of the developed methodology include excellent product yield in short duration, easy work-up procedure, green reaction solvent, ambient reaction parameters, wide substrate scope, high turnover number and good recyclability for multiple runs.

Hierarchical meso-micro porous Fe[sbnd]N[sbnd]C derived from tripolycyanamide-based microporous polymer as efficient electrocatalyst for oxygen reduction reaction

Designing porous FeNC nanomaterials with highly efficient active sites is an effective strategy for constructing high-performance oxygen reduction reaction (ORR) electrocatalysts. N-containing porous organic polymers (POPs) have emerged as promising candidates for the preparation of porous FeNC catalysts. Here, N-rich tripolycyanamide-based microporous polymer (TCAMP)-coated SiO2 nanospheres (SiO2@TACMP) were prepared as the precursors of an Fe-N doped hierarchical meso-micro porous carbon (Fe-N-HMC) electrocatalyst for the ORR. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM) characterizations demonstrated that the Fe-N-HMC catalyst possessed a higher content percentage of Fe-Nx active sites and a better distribution of Fe nanoparticles than its Fe-N doped microporous carbon (Fe-N-MC) counterpart. N2 adsorption–desorption isotherm analysis showed that Fe-N-HMC catalyst exhibited a hierarchical meso-micro porous system, with a Brunauer-Emmett-Teller (BET) surface area (SBET) of 733 m2 g−1 (∼2 times of Fe-N-MC’s SBET). As a result, Fe-N-HMC catalyst presented a highly efficient ORR performance with a half-wave potential of 0.856 mV, which is similar to the commercial grade 20 wt% Pt/C catalyst and superior to the Fe-N-MC catalyst. Moreover, the as-synthesized Fe-N-HMC catalyst displayed a better durability and methanol tolerance than the commercial Pt/C catalyst. Therefore, Fe-N-HMC shows great promise as an ORR catalyst for fuel batteries and metal-air cells due to its low-cost, high activity, and good stability.

Vitamin C modified crayfish shells biochar efficiently remove tetracycline from water: A good medicine for water restoration

In this study, crayfish shell biochar (CSB) was modified by introducing vitamin C (VC) with abundant surface functional groups. CSB was impregnated with VC at different ratios and its capacity to adsorb tetracycline (TC) from water was analyzed. The physicochemical properties of CSB were determined by N2 adsorption–desorption isotherm analysis, X-ray diffraction, and Fourier transform infrared spectroscopy. The effects of various factors on adsorption such as the pH, TC concentration, time, and salt ion concentrations were also investigated. Based on the chemical structure of VC, VC can provide CSB with more oxygen-containing functional groups such as hydroxyl groups. The results showed that the CSB modified with VC (CSB-VC) exhibited excellent adsorption of TC, and CSB-VC2 with an impregnation ratio of 2 (gVC/gCSB) had the greatest adsorption performance (saturated adsorption capacity, Qm = 293.36 mg/g), whereas the adsorption performance of CSB alone was about 50% lower (Qm = 172.16 mg/g). The optimal impregnation ratio VC improved the adsorption performance of CSB after modification to 70.4% of the original. Hydrogen bonding, p–p conjugation, pi-pi electron donor–acceptor effect, and π–π interactions were identified as the main adsorption mechanisms. CSB-VC2 was highly effective over a wide range of pH values and at high ion concentrations. Experiments demonstrated the effective regeneration of the adsorbent after multiple cycles, thereby indicating its excellent reusability. It should be noted that the adsorption capacity was good under different water quality conditions, and thus it should exhibit stable adsorption performance under complex water environment conditions.

Char of Tagetes erecta (African marigold) flower as a potential electrode material for supercapacitors

A char of Tagetes erecta flowers (TFC) was derived through simple thermal decompo­sition of Tagetes erecta flowers (TF). Physico-chemical properties of as-prepared TFC were evaluated using XRD, FESEM, FTIR, TGA, N2 adsorption-desorption isotherm analysis and water contact angle measurements. The practicality and applicability of TFC as promising electrode material in supercapacitors (SCs) were evaluated in full-cell configuration by performing electrochemical characterizations like CV, GCD and EIS on a lab-scale TFC-based symmetric SC. TFC exhibited a remarkable specific capacitance of 118.4 F g-1 at a constant current density of 0.2 A g-1 and a specific energy of 4.1 Wh kg-1 at specific power of 0.1 kW kg-1. TFC showed excellent cyclic stability by retaining 92 % of its initial capacitance even after 6000 GCD cycles at 2 A g-1. The superior capacitive behaviour and cyclic stability of TFC could be attributed to its good wettability towards water. This excellent supercapacitive performance of TFC estab­lishes it as a potential floral waste-derived carbon-based electrode material for SCs.

Efficient adsorption of tetracycline in aquatic system by thermally-treated sediment

The disposal of dredged sediment is a considerable challenge for environmental protection and resource utilization. In this study, the dredged sediment was thermally-treated to prepare as adsorbent and utilized for tetracycline adsorption. Sediments based adsorbents under different pyrolysis temperature and atmosphere (N2 and limited oxygen) were obtained and 600 °C and N2 atmosphere (600AN) exhibited maximum TC adsorption capacity (15.45 mg/g). SEM, N2 adsorption-desorption isotherm, XRD, FTIR and XPS analysis suggested larger pore volume, relatively higher surface area, effective pore size distribution and abundant surface functional groups were the main reasons. Moreover, the influence of key adsorption parameters, including adsorbent dosage, initial pH, coexisting ions, ionic strength, contact time, initial TC concentration and ambient temperature had also been investigated. Results revealed that TC adsorption by 600AN were more consistent with pseudo-second order kinetic and Freundlich isothermal models. Combined with characterization results, which reasonably inferred that the adsorption mechanisms of 600AN were mainly involved pore-filling effect, hydrogen bonding interaction and π-π EDA interaction. This work has provided a low-cost, high efficiency and promising method for the dredged sediment reduction and resource recovery.

Adsorption of crystal violet and methylene blue dyes using a cellulose-based adsorbent from sugercane bagasse: characterization, kinetic and isotherm studies

Biodegradable cellulose based on sugarcane bagasse is produced using alkaline treatment followed by bleaching method for dye removal. FTIR, Raman, SEM, EDS, XRD, and N2 adsorption–desorption isotherm analysis were utilized to characterize the surface morphology and functional groups of the sugarcane bagasse (SCB) and treated sugarcane bagasse (TSCB). The TSCB was investigated to remove of Crystal violet (CV) and Methylene blue (MB). Different factors influence the adsorption processes such as contact time, adsorbent dose, dye concentration, temperature, pH, and NaCl dose were studied. The Langmuir model was investigated to study the adsorption equilibrium behavior of CV and MB dyes by TSCB. A maximum adsorption capacities (qmax) of 107.5 and 112.9 mgg−1 was calculated for CV and MB-dyes, respectively. Also, the adsorption processes are physiosorption with average energy values of E = 1.151 and 1.101 KJmol-1 for CV and MB-dyes, respectively. The kinetic data of the investigated processes were controlled by the pseudo-second order (PSO) model with qe,cal (mgg−1) values of 59.3 and 58.9 mgg−1 for CV and MB-dyes, respectively. Suggesting that chemical mechanisms may influence the removal of CV and MB dyes. Overall, TSCB was found to be an effective, environmentally friendly, and low-cost material to remove of cationic dyes in this research.

Bio-metal-organic framework-based cobalt glutamate for CO2/N2 separation: Experimental and multi-objective optimization with a neural network

The outstanding properties of metal-organic frameworks (MOFs) have proven that this type of crystalline adsorbent has great potential in CO2 capture applications. Most of the MOF research studies on new functional MOFs are conducted to improve the performance of CO2 gas adsorption. Combined studies of material evaluation and process design on engineering issues in CO2 capture applications in industry are rarely carried out. In this study, the authors attempted to address engineering issues by developing a biometal-organic framework with the bioligand L-glutamic acid that has more practical fabrication cost than petrochemical MOFs. Herein, the demonstration of the prediction and optimization of CO2 adsorption capacity, selectivity, and heat of adsorption using a multiobjective genetic algorithm (MOGA) combined with an artificial neural network (ANN). The success of the Bio-MOF fabrication was evaluated by scanning electron microscopy, N2 adsorption-desorption isotherm analysis, thermal gravimetric analysis, X-ray diffraction, and Fourier transform infrared spectroscopy techniques. Furthermore, volumetric measurements were performed at several temperatures (27, 35 and, 50 °C). The isosteric heat of adsorption was then evaluated by an indirect method with the Clausius-Clapeyron (C-C) and Chakraborty, Saha, and Koyama (CSK) equations. Then, CO2/N2 selectivity was analysed by IAST techniques by regressing the experimental data with the Langmuir-Freundlich isothermal equation. The computational study by ANN and MOGA also gives satisfying results in balancing three requirements criteria. Thus, this study paved the way for the development of low-cost scalable MOF fabrication in industry by applying the optimization and balancing principles of the three objective functions.

Synthesis, characterization, and reactivity of a novel magnetically recyclable triazine‐based Cu–NNN–pincer complex

AbstractA new heterogeneous catalytic system containing triazine‐based copper(II) tridentate–NNN–pincer complex, covalently anchored to the amine‐functionalized silica‐coated Fe3O4 magnetic nanoparticles, Fe3O4@SiO2–NH–CCl–AT–Cu(II), was synthesized. Its structure was studied through the standard methods of FT‐IR, NMR, EDX, TGA, FE‐SEM, MAP images, XRD, ICP, and N2 adsorption–desorption isotherm analysis and utilized for the production of propargylamines by one‐pot A3 coupling of phenylacetylene, aldehydes, and secondary amines, attaining TOF values of up to 40,000 h−1. The impact of various solvents, reaction time, temperature, catalyst amount, and recyclability of the catalyst were studied to optimize reaction conditions. The catalyst was re‐examined five times, and no noteworthy reduction in activity was observed.

TUNGSTEN OXIDE DOPED TITANIA SUPPORTED ON TUD-C FOR PHOTOCATALYTIC REMOVAL OF METHYLENE BLUE

In this work, a series of mesoporous tungsten oxide (WO3) doped titania (TiO2) supported on Technische Universiteit Delft (TUD-C) (WO3-TiO2/TUD-C) were successfully prepared by the sol-gel method. X-ray diffraction (XRD) analysis showed that the samples’ crystallinity decreased after incorporation of WO3-TiO2 onto TUD-C, suggesting the successful incorporating WO3-TiO2 into the framework of TUD-C. N2 adsorption-desorption isotherm analysis indicated that the surface area, pore volume and pore size of WO3-TiO2/TUD-C increased significantly after loading onto TUD-C. The presence of tetrahedron frame structure Ti4+ and polytitanate in all the prepared samples were detected. Besides, all the WO3-TiO2 supported on TUD-C samples showed reduced band gap energy of 3.11 eV. The presence of zeolitic materials in the sample was confirmed by Fourier transform infrared spectroscopy, indicating the successfull formation of TUD-C. The Field Emission Scanning Electron Microsope (FESEM) images revealed the WO3-TiO2 were distributed uniformly on the surface of TUD-C. It has been demonstrated that the best photocatalytic activity for removal of methylene blue under UV light irradiation was achieved when WO3-TiO2/TUD-C was prepared with the molar ratio of Si to Ti is equal to 30 (WO3-TiO2/TUD-C(30)). The current research findings suggested that high pore size, surface area and crystallinity were the key factors for the high photocatalytic activity.Keywords: Photocatalyst, titania, TUD-C, tungsten oxide, methylene blue

Synthesis of Fe/H-ZSM-5 material by chemical vapor deposition method and its application for degradation of reactive dye

Fe containing nano ZSM-5 composites (Fe/H-ZSM-5) were successfully prepared by chemical vapor deposition method. The physical properties of Fe/H-ZSM-5 were characterized by X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS), scanning electron microscopy (SEM), N2 adsorption-desorption isotherm (BET) analysis. Effects of pH and H2O2 concentration were investigated. The best conditions were found to be pH of 3; 0.3 g.L−1 catalyst and reaction time of 60 min at room temperature. The novel Fe/H-ZSM-5 composite exhibited highly photocatalytic performance of RR-195 degradation and the conversion reached to the value of 92.3 % for after 60 min of reaction.

Magnetic covalent organic framework nanocomposites as a new adsorbent for the determination of polycyclic aromatic hydrocarbons in water and food samples.

A magnetic covalent organic framework nanocomposite (Fe3O4@COF(Tp-NDA)) was synthesized via a solvothermal method, used as a magnetic adsorbent for the extraction of polycyclic aromatic hydrocarbons (PAHs) from lake water, tea, coffee, and fried chicken, and detected using a high performance liquid chromatography-ultraviolet detector. The synthesized magnetic adsorbent was characterized via transmission electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, N2 adsorption-desorption isotherm analysis and vibrating sample magnetometry. Parameters that affected the extraction conditions and desorption conditions were optimized. Adsorption equilibrium could be attained within 3 min. The prepared magnetic material could be reused 10 times. The limits of detection and quantification were 0.05-0.25 μg L-1 and 0.17-0.83 μg L-1, respectively. The recovery was 74.6-101.8% with a relative standard deviation of below 4.2%. The method was successfully used to detect PAHs in various samples.

Experimental design via NaOH activation process and statistical analysis for activated sugarcane bagasse hydrochar for removal of dye and antibiotic

In this study, hydrochar derived from SB was activated with sodium hydroxide (NaOH) by the cold alkali activation method, to increase the number of oxygenated functional groups, as well as enhance its porosity by clearing pore blockages. Response surface methodology by central composite design (RSM-CCD) was employed to investigate the effects of NaOH activation process parameters (NaOH concentration (A), hydrochar mass ratio (B) and activation time (C)) on prepared hydrochar towards three responses; activated hydrochar (AHC) yield, tetracycline (TC) antibiotic removal and crystal violet (CV) dye removal. Through the analysis of variance (ANOVA) tests, the significance sequences of single factor affecting were B > C > A for AHC yield, A > B > C for both TC removal and CV removal. However, the significant interaction effect for both AHC yield and TC removal was observed with BC only. Meanwhile, CV removal was noticed with different result whereby two significant interaction effects (AB and AC) were observed. Through optimisation study, optimised AHC (AHCop) was generated by maximising all three responses and it was predicted to generate 54.23% yield with TC and CV adsorption capacity of 22.60 mg g−1 and 47.97 mg g−1. A relative standard deviation (R.S.D) of 1.32%, 0.97% and 2.14% (n = 3) were obtained for AHC yield, TC and CV removal, respectively. Following optimisation, AHCop was characterised by N2 adsorption-desorption isotherm analysis, Field Emission Scanning Electron Microscopy, Fourier Transform Infrared Spectroscopy, and Thermogravimetric analysis. In brief, the physiochemical characteristics of AHCop were observed with meso and macro pore structures, numerous microsphere-like particles with crack surfaces, abundance functional groups, strong π-π reaction and high thermal stability. The optimisation study was succeeded to develop AHCop at a higher yield and remove both TC and CV at higher adsorption capacity compared to before activation.

Eco-Friendly and Solvent-Less Mechanochemical Synthesis of ZrO2–MnCO3/N-Doped Graphene Nanocomposites: A Highly Efficacious Catalyst for Base-Free Aerobic Oxidation of Various Types of Alcohols

In recent years, the development of green mechanochemical processes for the synthesis of new catalysts with higher catalytic efficacy and selectivity has received manifest interest. In continuation of our previous study, in which graphene oxide (GRO) and highly reduced graphene oxide (HRG) based nanocomposites were prepared and assessed, herein, we have explored a facile and solvent-less mechanochemical approach for the synthesis of N-doped graphene (NDG)/mixed metal oxide (MnCO3–ZrO2) ((X%)NDG/MnCO3–ZrO2), as the (X%)NDG/MnCO3–ZrO2 nano-composite was synthesized using physical grinding of separately synthesized NDG and pre-calcined (300 °C) MnCO3–ZrO2 via green milling method. The structures of the prepared materials were characterized in detail using X-ray powder diffraction (XRD), Field Emission Scanning Electron Microscope (FESEM), Energy Dispersive X-Ray Analysis (EDX), Fourier-transform infrared spectroscopy (FTIR), Raman, Thermogravimetric analysis (TGA), and N2 adsorption-desorption isotherm analysis. Besides, the obtained nanocomposites were employed as heterogeneous oxidation catalyst for the alcohol oxidation using green oxidant O2 without involving any surfactants or bases. The reaction factors were systematically studied during the oxidation of benzyl alcohol (PhCH2OH) as the model reactant to benzaldehyde (PhCHO). The NDG/MnCO3–ZrO2 exhibits premium specific activity (66.7 mmol·g−1·h−1) with 100% conversion of PhCH2OH and > 99.9% selectivity to PhCHO after only 6 min. The mechanochemically prepared NDG based nanocomposite exhibited notable improvement in the catalytic efficacy as well as the surface area compared to the pristine MnCO3–ZrO2. Under the optimal circumstances, the NDG/MnCO3–ZrO2 catalyst could selectively catalyze the aerobic oxidation of a broad array of alcohols to carbonyls with full convertibility without over-oxidized side products like acids. The NDG/MnCO3–ZrO2 catalyst were efficiently reused for six subsequent recycling reactions with a marginal decline in performance and selectivity.

Preparation of ion-exchange resin via in-situ polymerization for highly selective separation and continuous removal of palladium from electroplating wastewater

To separate palladium (Pd) from electroplating wastewater, a novel mesoporous ion-exchange resin (SiAcyl) was prepared with the loading rate of 27.3 wt% and the cross-linking degree of 10 wt%. It was synthesized by using macroporous silica as inorganic carrier, acrylic acid, and allyl acetoacetate as monomers, EGDMA as cross-linking agent, AIBN as chemical initiator, dimethyl sulfoxide as diluent. The as-prepared SiAcyl resin was characterized by SEM-EDS, TG-DSC, N2-adsorption–desorption isotherm analysis, which revealed its characterization of high loading rate, mesoporous structure, and large specific surface area. It exhibited significant advantages in Pd separation and recovery, such as significant selectivity (SFPd/M > 124 in pH = 1.95 nitric acid solution), remarkable adsorption capacity (92.6 mg·g−1 Pd), and excellent reusability (n > 5). Moreover, the column separation technique was employed to better evaluate the feasibility of separation of Pd from actual electroplating wastewater by SiAcyl resin that a recovery yield about 100% of Pd and complete separation of Pd from other metal ions were obtained. Compared with several traditional commercial resins, SiAcyl resin exhibited great advantages and potential in industrial applications. Furtherly, XPS and FT-IR analysis demonstrated the ion-exchange between H+ (from –COOH) and Pd(II) is the mechanism during the whole adsorption process.

Facile Route to Synthesize Pore Expanded Platelet SBA-15 for Enhanced Amidoxime-Functionalization and Efficient Extraction of U(VI) from Aqueous Solution

Short channel platelet SBA-15 mesoporous material is one of the effective adsorbent for the recovery of U(VI) from aqueous solution. Nevertheless, the defect is that the mesoporous size limits the total stripping of attached U(VI) in recycling use and the increasing densities of organic groups after functionalization. Thus, a simple and controllable method was adopted to prepare SBA-15-type material with expanded pore channel by adding trimethylbenzene in synthesis procedure. The structure, morphology and functional groups were characterized by scanning electron microscope, powder X-ray diffraction, thermogravimetric analysis, transmission electron microscope, FTIR and N2 adsorption-desorption isotherm analysis. Furthermore, the adsorption behavior of obtained product was test under various factors such as initial concentration, pH, elution rate and contact time. The pore expanded platelet SBA-15 exhibited higher U(VI) adsorption capacity, higher elution rate, and more bearing of amidoxime groups. Due to the higher amidoxime groups, the adsorption capacity of U(VI) on the amidoxime functionalized pore-expanded SBA-15 was 674mg-U g−1. The results show that the simple and controllable pore-expanded method is an effective strategy to enhance the elution effect and increase grafting amount of organic groups on the mesoporous materials.

Synthesis of Fe-Cu/MCM-41 nanocomposite and its application for treatment of Reactive Red 195

A series of Fe-Cu/MCM-41 nanocomposites were synthesized by dispersion of Fe-Cu on mesoporous silica MCM-41 obtained from natri silicat. The physical properties of Fe-Cu/MCM-41 were characterized by X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS), scanning electron microscopy (SEM), x-ray photoelectron spectroscopy (XPS), N2 adsorption-desorption isotherm (BET) analysis. Effects of pH and H2O2 concentration were investigated. The best conditions were found to be pH of 3; 0.3 g.L−1 catalyst and reaction time of 60 min at room temperature. The novel Fe-Cu/MCM-41 composite exhibited highly photocatalytic performance of RR-195 degradation and the conversion reached to the value of 98.13 % for the 10Fe-2Cu/SBA-15 after 60 min of reaction.