Chemical Impregnation Research Articles

Sonochemical post-synthesis modification of Y zeolite with iron species

Faujasite is a zeolite that, when in a Y structure, is widely used as a catalyst to produce fuel by fluid catalytic cracking (FCC) and is recently being investigated for applications in sustainable processes. Hence, there is an increased interest in modifying Y zeolites with metals such as Fe to improve and optimize their catalytic properties. Several post-synthesis methods such as chemical vapor deposition, impregnation and ion exchange have been explored for the introduction of Fe. Nevertheless, these currently developed methods can be time-consuming and unable to selectively tune the Fe species. Therefore, this study explores the use of ultrasonic irradiation in a liquid state modification of a Fe-exchanged Y zeolite (FeY) in a buffer solution with different pH values (5 and 9) and oxidation states of Fe ions (ferrous and ferric) for the introduction of Fe species. At the tested ultrasonic modification conditions, the zeolitic structure was preserved with slight Si/Al ratio and pore structure adjustments in correlation with the introduced Fe species (ions, hydroxides and oxides). Setting the sonochemical method as a potential path for the search of reaction conditions for the design and fabrication of Fe-modified zeolitic materials with tuned properties for a wide range of applications.

A Review on the Effect of Wood Surface Modification on Paint Film Adhesion Properties

Wood surface treatment aims to improve or reduce the surface activity of wood by physical treatment, chemical treatment, biological activation treatment or other methods to achieve the purpose of surface modification. After wood surface modification, the paint film adhesion performance, gluing performance, surface wettability, surface free energy and surface visual properties would be affected. This article aims to explore the effects of different modification methods on the adhesion of wood coating films. Modification of the wood surface significantly improves the adhesion properties of the paint film, thereby extending the service life of the coating. Research showed that physical external force modification improved the hydrophilicity and wettability of wood by changing its surface structure and texture, thus enhancing the adhesion of the coating. Additionally, high-temperature heat treatment modification reduced the risk of coating cracking and peeling by eliminating stress and moisture within the wood. Chemical impregnation modification utilized the different properties of organic and inorganic substances to improve the stability and durability of wood. Organic impregnation effectively filled the wood cell wall and increased its density, while inorganic impregnation enhanced the adhesion of the coating by forming stable chemical bonds. Composite modification methods combined the advantages of the above technologies and significantly improved the comprehensive properties of wood through multiple modification treatments, showing superior adhesion and durability. Comprehensive analysis indicated that selecting the appropriate modification method was key for different wood types and application environments.

Oxygen-functionalization of unique hierarchical carbon nanosheet fishtail-like for synergistically enhanced capacitive performance supercapacitor

The optimization of high-performance supercapacitors with enhanced electrochemical properties using biomass-based activated carbon is a challenging task. To overcome this, a novel strategy was used to create functional nanocarbon with a hierarchical-nanosheet structure based on bio-waste of Clausena Excavata Burm F (CEBF) leaves. The precursor was optimized through different chemical impregnation concentrations without the addition of any other substances. This resulted in a unique hierarchical carbon nanosheet fishtail-like with a specific surface area of 828.679 m2 g−1. The high carbon content of CEBF (up to 88.58%) and 4.46% oxygen as heteroatoms showed a beneficial pseudocapacitance effect. The electrochemical properties of CEBF-activated carbon were excellent, with a specific capacitance of 248 F g−1. The optimal energy density reached 33.8267 Wh kg−1, and the power density was 4.755 kW kg−1 at 10 A g−1. These findings suggest that CEBF biomass has significant potential as a source of hierarchical carbon nanosheet that enhances high-performance electrochemical supercapacitors.

Synthesis and characterization of UHMWPE composite fabrics treated with bis-diazirine crosslinker and silica/PEG shear thickening fluid

This study focuses on investigating the mechanical behavior of a set of new chemically-treated crosslinked Ultra-High Molecular Weight Polyethylene (UHMWPE) plain-weave fabrics with varying areal densities, and impregnated with a shear thickening fluid (STF). The evaluation of the materials performance included tensile, bias-extension (shear), puncture, and drop tower tests under low rates of loading. For comparison purposes, three different sample groups were considered: untreated fabrics, crosslinked fabrics, and crosslinked fabrics with STF. The STF impregnation was composed of fumed silica nanoparticles (NPs) suspended in a polyethylene glycol (PEG) medium. Both the individual and combined effects of the chemical crosslinking and STF impregnation on the UHMWPE fabrics were explored. Additionally, the impact of strain rate on the tensile and shear behavior of various material groups was examined. The findings revealed that the addition of the crosslinker and shear thickening fluid significantly improves the puncture resistance of the base UHMWPE fabric, by as high as 92 %. The energy absorption and specific energy absorption of the UHMWPE fabric also increased up to 55 % and 16 %, respectively, with the addition of both STF and crosslinker.

Elaboration of fibrous structured activated carbon from olive pomace via chemical activation and low-temperature pyrolysis

The objective of this study is to examine the preparation of activated carbon with a fibrous structure obtained from olive pomace through a chemical activation process using phosphoric acid (H3PO4) as the activating agent under air at a lower temperature. According to the findings, the most effective conditions to achieve high-performance activated carbon were 22 vol% of H3PO4, a 2-h chemical activation impregnation residence time at 50 °C, and a 500 °C pyrolysis temperature for 1 h. Structural analysis revealed that activated carbons possess highly developed textural and structural properties, resulting in an iodine value of 923 mg/g and a specific surface of 1400 m2/g. In addition to its microporosity, the produced carbon exhibits a highly developed fibrous structure, providing excellent adsorption properties. To confirm these results, SEM, FT-IR, XRF, XRD, Raman, and TGA techniques were employed. The fibrous carbon produced will expand the use of renewable carbon materials for removing various types of contaminants, including organic and inorganic pollutants in water, and numerous other industrial applications.

A parametric study on chemical activator selection and soaking procedure development for barium incorporation in concurrent activated and surface modified palm kernel shell derived activated carbon

The concurrent activation and surface modification (CAM) process is an integrated process used to synthesise palm kernel shell derived activated carbon (PKSdAC) in this study. CAM involves chemical activation and surface modification via metal impregnation in one process. This study investigated the usage of different acids as chemical activators and different soaking procedures for impregnating barium (Ba) in CAM-PKSdAC. It shows that chemical impregnation of PKS using 10% sulphuric acid (H2SO4) mass loading via two soaking steps can impregnate a high Ba amount of 0.86–2.98 wt. % in CAM-PKSdAC, compared to one soaking step. The two soaking steps procedure reduced the overage formation of BaSO4 from sealing the pores of PKS. Comparing HCl and H2SO4, at 30% acid mass loading, the impregnation of PKS with H2SO4 produced a higher impregnated Ba amount in CAM-PKSdAC. BaSO4 generated from the reaction between H2SO4 on the PKS surface with BaCl2 solution causes a reduction reaction at high temperatures. BaSO4 reacted with a carbon-reducing agent and is reduced to barium sulphide (BaS), impregnating Ba on CAM-PKSdAC. In conclusion, H2SO4 was found to be the suitable chemical activator with two soaking steps for the CAM process.

Evaluating chemi-mechanical pulping processes of agricultural residues: High-yield pulps from wheat straw for fiber-based bioproducts

This work evaluates the feasibility of APMP (alkaline peroxide mechanical pulping) and CTMP (chemi-thermomechanical pulping) of wheat straw as small-scale, low-capital expenditure pulping process to produce high-yield pulps for fiber-based bioproducts. APMP and CTMP wheat straw pulps were characterized in terms of pulping yield, freeness, ISO brightness, and fiber morphology. Additionally, both pulps were evaluated for tissue paper applications and benchmarked against BEK (bleached eucalyptus kraft) market pulp. APMP wheat straw pulps presented higher yield (75.2 – 79.8 %) compared to CTMP (69.1 – 80.6 %), depending on cooking chemicals and chemical charge during the chemical impregnation stage. The final brightness of APMP pulps varied from 36.4 % to 37.8 % ISO when sodium hydroxide and hydrogen peroxide were used as pulping agents without additional chemical additives. However, the brightness of APMP pulps can be increased up to 49.7 % ISO by using additional chemical additives such as EDTA (chelating agent), sodium silicate (peroxide stabilizer), or by employing a multi-stage chemical impregnation strategy. Both pulps produced fibers with similar morphological properties. A comparison of tissue-making properties showed that APMP pulps produced bulkier handsheets with higher water absorption capacity and better softness than CTMP pulps. However, CTMP pulps exhibited a higher tensile index than APMP pulps for a given pulp freeness. The results indicate that non-wood fibers, such as those derived from wheat straw, could be a promising alternative for use in fiber-based bioproducts such as hygiene tissue.

The Effect of Loading W&V:TiO2 Nanoparticles with Noble Metals for CH4 Detection

TiO2 nanoparticles (NPs) doped with W (W:TiO2), double-doped with W and V (W&V:TiO2), and loaded with noble metals (W:TiO2 @Pt/Pd/Ag and W&V:TiO2@Pt/Pd/Ag) were synthesized by laser pyrolysis followed by chemical impregnation and reduction. Due to its exceptional properties, TiO2 is considered a key material being used in a wide range of applications. To improve its detection activity, the increase in the specific surface of the material, and the presence of defects in its structure play a decisive role. Doped and double-doped TiO2 nanoparticles with dimensions in the range of 25–30 nm presented a mixture of phases corresponding to titania, with the anatase phase accounting for the majority (95%). By loading these nanoparticles with small particles of noble metals, a significant increase in the specific surface area by three or even five times the original values was achieved. Sensitive thin films for surface acoustic wave (SAW) sensors were made with the NPs, embedded in polyethyleneimine (PEI) polymer and deposited by spin-coating. Each sensor was tested at CH4 concentrations between 0.4 and 2%, at room temperature, and the best results were obtained by the sensor with NPs doped with V and decorated with Pd, with a limit of detection (LOD) of 17 ppm, due to the strong catalytic effect of Pd.

Potato peel carbon dots produced via fixed bed pyrolysis reactor decorated 1-D TiO2 nanorods for rapid removal of methylene blue, Cr (VI), Escherichia coli, and Aspergillus niger

In this work, new type carbon quantum dots produced from waste of biomass were used as a dopant molecule in order to investigated photocatalytic properties of TiO2 nanorods structures. Low-cost and eco-friendly carbon quantum dots (CQDs) were obtained via slow pyrolysis of potato peels (PP) as a biomass waste without any chemicals by fixed bed pyrolysis. Potato peel quantum dots (P-CQDs) decorated TiO2 nanorods (P-CQDs/TNRs) were synthesized were by utilizing their high specific surface area, good dispersion, abundant surface functional groups. (P-CQDs) were imposed on the surface of the one-dimensional TiO2 nanorods fabricated via chemical impregnation method for P-CQDs/TiO2 nanorods (P-CQDs/TNRs) that TiO2 nanorods have been fabricated by hydrothermal route. Characteristic properties of as-prepared P-CQDs/TNRs photocatalysts were characterized employing TGA, XRD, XPS, FE-SEM/EDS, HRTEM, FTIR, fluorescence and UV–vis spectroscopy, resp. The photocatalytic activity of as-prepared P-CQDs/TNRs were investigated for methylene blue, hexavalent chromium, Escherichia coli and Aspergillus niger under UV-A. The obtained results suggest that the photocatalytic activity of P-CQDs/TNRs composites was slightly enhanced as compared to that of TNRs. The scenario behind the superior photocatalytic activity of P-CQDs/TNRs may be having a synergetic effect between P-CQDs molecules and the surface of TNRs, and also the design of the charge-transfer channel of TNRs. Moreover, the carbon derived from a natural green source possesses the various functional groups such as CC, C-OH, C-O-C, CO, and when these functional groups deposited to the surface of the TiO2 nanorods, newly formed nanocomposites can improve the visible light-driven photocatalytic activity.

Cu nanowire – impregnated activated carbon fiber for antibacterial applications

Metal nanowires are a 1D structure possessing distinct properties suitable for diverse applications. Copper nanowires (Cu NW) have garnered attention in recent times, particularly as an antibacterial material. Nevertheless, their utilization as a bandage or dressing material necessitates a suitable support, an aspect that remains largely unexplored. In this study, we have developed activated carbon fiber (ACF)-supported Cu NW using the chemical reduction and wet impregnation methods. Tested against Escherichia coli and Staphylococcus aureus, Cu NW/ACF exhibits 83 - 86% reduction in the bacterial growth. The improved antibacterial activity of the material is attributed to the relatively slow release of Cu ions from Cu NW, attributed to the Kelvin effect. Biocompatibility test confirms less than 1.5% hemolysis of erythrocytes, indicating the potential application of the composite as a bandage or dressing material.

MgO Modified by X2, HX, or Alkyl Halide (X = Cl, Br, or I) Catalytic Systems and Their Activity in Chemoselective Transfer Hydrogenation of Acrolein into Allyl Alcohol.

A new type of catalyst containing magnesium oxide modified with various modifiers ranging from bromine and iodine, to interhalogen compounds, hydrohalogenic acids, and alkyl halides have been prepared using chemical vapor deposition (CVD) and wet impregnation methods. The obtained systems were characterized using a number of methods: determination of the concentration of X- ions, surface area determination, powder X-ray diffraction (PXRD), surface acid-base strength measurements, TPD of probe molecules (acetonitrile, pivalonitrile, triethylamine, and n-butylamine), TPD-MS of reaction products of methyl iodide with MgO, and Fourier transform infrared spectroscopy (FTIR). The catalysts' activity and chemoselectivity during transfer hydrogenation from ethanol to acrolein to allyl alcohol was measured. A significant increase in the activity of modified MgO (up to 80% conversion) in the transfer hydrogenation of acrolein was found, while maintaining high chemoselectivity (>90%) to allyl alcohol. As a general conclusion, it was shown that the modification of MgO results in the suppression of strong basic sites of the oxide, with a simultaneous appearance of Brønsted acidic sites on its surface. Independently, extensive research on the reaction progress of thirty alkyl halides with MgO was also performed in order to determine its ability to neutralize chlorinated wastes.

Study on the corrosion resistance of new reticulated organic polymerized film on copper foil surface

In response to the policy of energy saving and emission reduction, the field of new energy vehicles is booming, and along with it, the technical requirements for lithium-ion batteries are becoming more and more stringent. Electrolytic copper foil, as the anode collector material of lithium batteries, seriously affects the progress of lithium technology, and electrolytic copper foil with high corrosion and oxidation resistance is the key to ensuring its performance. Experimentally, the BTA-Si passivation film layer was constructed on the surface of electrolytic copper foil by compounding benzotriazole (BTA) and silane coupling agent (JH-M902) with an easy-to-operate chemical impregnation method. The results of electrochemical analysis and characterization showed that JH-M902 hydrolyzed to produce Si-OH and then dehydrated and polymerized with Cu-OH to form Si-O-Cu or partially dehydrated and polymerized with each other to form Si-O-Si, which formed an intertwined organic reticulation film on the electrolytic copper foil. At the same time, BTA and copper oxides form a BTA-Cu complex, which is adsorbed and perpendicular to the copper foil. The combination of the two can not only make up for the gap in the organic mesh layer but also anchor the mesh layer, thus inhibiting its desorption in harsh external environments. Immersed in 3.5 wt% NaCl, the self-corrosion current density (icorr) of BTA-Si passivation film is only 1.115 × 10−7 A/cm2, and the corrosion inhibition rate as high as 99.56 %, which is far better than that of the single BTA and Si passivation film. In addition, the BTA-Si passivation film is smooth, dense, and thin, which significantly improves the corrosion resistance of copper foil without changing its original structure.

Construction of g-C3N4/SnSe2/H-TiO2 Ternary Heterojunction for High-Performance Photodetectors

Two-dimensional layered materials have been widely used in the field of photodetectors because of their unique photoelectric properties. Among them, the multi-heterojunction based on two-dimensional materials with high carrier separation efficiency is expected to be designed as a high-performance photodetector (PD). This work focuses on the fabrication of g-C3N4/SnSe2/H-TiO2 ternary heterojunctions for photodetectors, obtained by depositing SnSe2 and g-C3N4 nanosheets onto TiO2 nanotube arrays using chemical vapor deposition and impregnation methods, respectively. The formation of the g-C3N4/SnSe2/H-TiO2 ternary heterojunction enhances and broadens absorption in the ultraviolet-visible range. Photoelectrochemical measurements have confirmed that the fabricated g-C3N4/SnSe2/H-TiO2 ternary heterojunction photodetector exhibits remarkable light detection capabilities at 370, 450, and 520 nm, meaning broadband photodetection behavior. Notably, under light illumination of 370 nm wavelength, it demonstrates a high responsivity of 2.742 A W−1, an impressive detectivity of 5.84 × 1010 Jones, an external quantum efficiency of 9.21 × 102 %, and excellent stability. This high performance can be attributed to the effective separation and transfer of photogenerated carriers within the ternary heterojunction, significantly enhancing the photoresponse. The construction of the novel broadband-responsive ternary g-C3N4/SnSe2/TiO2 heterojunction holds promise for driving the future development of wideband, high-performance, and highly integrated photodetectors.

Hexavalent chromium adsorption from aqueous solution utilizing activated carbon developed from Rumex abyssinicus

The indiscriminate release of chromium-saturated effluent into water bodies has raised concerns regarding its effect on human health and environmental ecology. Therefore, this research aimed to remove hexavalent chromium from an aqueous solution utilizing activated carbon developed from Rumex abyssinicus. The adsorbent was prepared through chemical impregnation with H3PO4 and then thermally activated at 500 °C for 2 h. The optimization of the adsorption experiments was performed using the Box‒Behnken approach of response surface methodology. The characterization of the prepared activated carbon revealed good quality in terms of its amorphous structure, maximum specific surface area of 1722.9 m2/g and porous surface. Furthermore, the optimization results showed that a maximum removal efficiency of 95.97 % was attained at an optimum working pH of 3, a contact time of 60 min, an initial chromium concentration of 70 mg/L and an adsorbent dosage of 0.6 mg/100 mL. The Langmuir isotherm model was found to have the best fit with the experimental data. Moreover, the kinetics study revealed that a pseudo-second-order model fit the data best, indicating the occurrence of chemisorption. Overall, this study suggested that Rumex abyssinicus could be an effective adsorbent for removing hexavalent chromium from aqueous solutions.

ADSORPTION OF CATION DYE USING ACTIVATED CARBON DERIVED FROM GOLDEN SHOWERSEED POD ( C ASSIA FISTULA)

This study investigated the use of Golden shower seed pod (cassia fistula) as an adsorbent for the removal of cationic dye in a batch system. The raw material was Carbonized at 600 oC for one hour to obtain a purely carbonized material; then impregnated with NaOH of 0.1M and allowed to stay for 24 hours to obtain the desired GS-AC activated carbon. The adsorbent was characterized using scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, and energy-dispersive X-ray fluorescence (EDXRF) elemental composition analysis. The effects of adsorbent dosage and contact time on the adsorption process were studied in a batch system. The results revealed that, there was good enhancements in pores of the adsorbent GS-AC due to the chemical impregnation. The FTIR spectra showed the presence C-H, NH 2, C-O, and S=O functional groups indicating a favourable surface for adsorption. Batch studies indicated that, the methylene blue uptake decreased with increase in the GS-AC dosage. The amount of Methylene blue adsorbed onto GS-AC increased with time and subsequently remained constant at some point in time with maximum uptake at 500 mg/l. Thus, adsorption capacity of methylene blue increased with longer contact time, indicating a stronger interaction between the adsorbent and the dye. Based on the findings, Golden shower seed pod (cassia fistula) impregnated with NaOH can be used as an alternative and suitable material for cationic dye removal from liquid phase.

Preparation and Study of Ti3C2Tx MXene–Deficient In Situ Anchored Fe−Co Alloy Nanoparticle Electrocatalyst for Hydrolysis and Hydrogenolysis

AbstractThe novel two–dimensional MXene material Ti3C2Tx has the advantages of a large specific surface area, adjustable band gap, good electrical conductivity, and high stability. However, the precipitation of hydrogen via electrolytic water splitting over Ti3C2Tx has unacceptably slow kinetics. In this paper, Co nanoparticles were incorporated on the Ti3C2TxMXene surface via electrostatic adsorption by utilizing the intrinsic MXene defects generated during the etching process. Next, a Fe−Co alloy structure was also constructed on the Ti3C2TxMXenesurface by wet chemical impregnation method using the principle of galvanic coupling substitution. The prepared catalyst had an overpotential of 118 mV at a current density of 10 mA‐cm−2 and a Tafel slope of 97.56 mV dec−1. The Fe−Co alloy structure accelerated the kinetic hydrogen precipitation step, and Fe−Co/Ti3C2Txshowed excellent stability when used in a water electrolysis process for 11 h. This work offers a promising strategy for the synthesis of intrinsically defective synthetic alloy MXene structures.

Comparative Ablation Behaviors of 2D Needled C/SiC and C/SiC-ZrC Composites

To investigate the effect of ZrC on the ablative properties of C/SiC composites in a high-temperature environment, the oxidative ablation of C/SiC and C/SiC-ZrC composites at high-temperatures was examined through ablation tests. In this study, two ceramic matrix composites, C/SiC and C/SiC-ZrC, were prepared by chemical vapor deposition and precursor impregnation pyrolysis. The ablation properties of the materials were tested and analyzed using an oxyacetylene flame to simulate a high-temperature environment. The results revealed that the line ablation rate of C/SiC-ZrC was 8.48% and 20.81% lower than that of C/SiC at 30 s and 60 s, respectively. At the same ablation time, the depth of the crater resulting from erosion of the C/SiC material by the high-temperature airflow was deeper than that of C/SiC-ZrC. The traces of the fibers subjected to erosion were more prominent. In a longitudinal comparison, the mass ablation rate of C/SiC-ZrC material decreased with the increase in time, while the line ablation rate initially increased rapidly and then decreased. From 30 s to 90 s of ablation, the line ablation rate and mass ablation rate decreased by 55.62% and 89.5%, respectively. The overall trend for both rates was a decrease with the increase in time. Under the same ablation time, the ablation rate of C/SiC-ZrC was generally lower than that of C/SiC. This is because the generated molten ZrO2 was more viscous and denser than SiO2, effectively blocking oxidizing gases from penetrating the interior of the material. The molten ZrO2 provided better protection for the substrate in the high-temperature environment.

The Influence of SnO2 and Noble Metals on the Properties of TiO2 for Environmental Sustainability

In order to find solutions to current worldwide environmental problems, it is crucial to develop sustainable nanomaterials, ideally with multifunctional properties. Considering this, novel TiO2-SnO2@NMs (noble metals: Au and Ag) composites, for use as sustainable nanomaterials, were successfully prepared via a two-step synthesis process consisting of laser pyrolysis followed by the chemical impregnation of the collected materials with noble metals. The addition of SnO2 favors the transformation of TiO2 from a mixture with a majority Anatase phase to one with a Rutile phase majority. With consideration for their level of environmental toxicity, the features of the synthesized nanomaterials were structurally, morphologically, and optically described and assessed for environmental protection applications as gas sensors and photocatalysts. In the case of the Surface Acoustic Wave sensor, based on a pure TiO2 nanopowder, a notable difference in the frequency shift was detected in comparison to the other examined sensors. All sensors responded to the CH4 concentrations tested (0.02–0.1%). On the other hand, when methyl orange was photodegraded under visible light, the results obtained using NMs for decoration revealed that the photocatalytic activity of TiO2-SnO2@NMs was significantly improved compared to the TiO2-SnO2 binary composite, which already has an enhanced photocatalytic activity, compared to pure TiO2. Overall, this work produces nanoparticles that exhibit better sensory and photocatalytic features, as well as higher levels of biocompatibility with skin cells, for use as eco-friendly nanomaterials for a sustainable future.

Sequentially optimized process towards sustainable synthesis of activated carbon from wild thornbush for 4-nitrophenol and industrial effluent treatment.

Environmental nuisance thornbush Prosopis juliflora was utilized as an inexpensive and renewable biomass raw material for the sustainable production of activated carbon. Previously, the sequential muffle furnace-microwave arrangement was effective with acid activation for activated carbon synthesis. However, the intermediate synthesis steps were not optimized. In this work, we have optimized the intermediate steps, viz. chemical impregnation, carbonization, and microwave activation. Sequential optimization for base activation was developed and compared with acid activation. The base-activated carbon (BAC) exhibited a more crystalline nature and faster uptake kinetics than AAC. BAC demonstrated an adsorption capacity of 576mg/g for 4-nitrophenol (4-NP) surpassing that of optimized acid-activated carbon (AAC) by 45%. The optimal base activation required 1.85 times lower microwave energy than that of the acid activation. BAC exhibited significantly higher BET surface area (1319 m2/g) and micropore volume (0.524 cm3/g) which were about 28% and 26% higher than those of AAC. When compared to biochar obtained from the same thornbush, the BAC exhibited an 11-fold increase in adsorption capacity. The adsorbents could be easily regenerated with ethanol and used up to five cycles. Adsorption using BAC also could achieve 80% COD removal for industrial wastewater, while AAC led to 61% removal. Continuous packed column with BAC revealed a breakthrough time of 3.5h for industrial effluent while for 500mg/L 4-nitrophenol, it was 25h. Prosopis juliflora thornbush, an environmental nuisance, could be converted into a high-capacity adsorbent for environmental remediation after careful sequencing and optimization of the intermediate synthesis steps.

Preparation of Copper-Based Catalysts for Obtaining Methanol by the Chemical Impregnation Method.

This paper presents the preparation of heterogeneous catalysts for the direct hydrogenation process of CO2 to methanol. The development of the modern chemical industry is inextricably linked to the use of catalytic processes. As a result, currently over 80% of new technologies introduced in the chemical industry incorporate catalytic processes. Since the basic factor of catalytic processes is the catalysts, the studies for the deepening of the knowledge regarding the nature of the action of the catalysts, for the development of new catalysts and catalytic systems, as well as for their improvement, represent a research priority of a fundamental or applied nature. The Cu/ZnO/Al2O3 catalyst for the synthesis of green methanol, using precursors of an inorganic (copper nitrate, denoted by Cu/ZnO/Al2O3-1) and organic (copper acetate, denoted by Cu/ZnO/Al2O3-2) nature, are obtained by chemical impregnation that includes two stages: preparation and one of calcination. The preparation methods and conditions, as well as the physico-chemical properties of the catalyst precursor, play a major role in the behavior of the catalysts. The prepared catalysts were characterized using atomic adsorption analysis, scanning electron microscopy (SEM) with energy dispersive X-ray (EDX) analysis, specific surface area and pore size analyses, adsorption, and the chemisorption of vapor (BET).