Brunauer Emmett Teller Surface Area Research Articles

Sustainable Napier Grass (Pennisetum purpureum) Biochar for the Sorptive Removal of Acid Orange 7 (AO7) from Water

The unregulated discharge of synthetic dyes from various anthropogenic and industrial activities has resulted in the contamination of different environmental compartments. These dyes can contaminate water bodies, soil, and even the air, resulting in many environmental and health issues. True colors may persist for long periods, thereby affecting the aesthetics and ecology of dye-contaminated areas. Furthermore, they pose potential risks to aquatic life and human health through the ingestion or absorption of dye-contaminated water or food. Acid orange 7 (AO7) is a synthetic azo dye used in the textile, tanning, food, pharmaceutical, paint, electronics, cosmetics, and paper and pulp industries. AO7 can have various human health implications, such as dermatitis, nausea, severe headache, respiratory tract irritation, and bone marrow depletion, due to its high toxicity, mutagenicity, and carcinogenicity. Efforts to regulate and mitigate dye pollution (AO7) are crucial for environmental sustainability and public health. Therefore, this study aimed to remove AO7 from water using sustainable biochar. This objective was accomplished by pyrolyzing dried Napier grass at 700 °C to develop affordable and sustainable Napier grass biochar (NGBC700). The developed biochar was characterized for its surface morphology, surface functional groups, surface area, and elemental composition. The yield, moisture content, and ash content of the NGBC700 were approximately 31%, 6%, and 21%, respectively. The NGBC700’s BET (Brunauer–Emmett–Teller) surface area was 108 . Batch sorption studies were carried out at different pH levels (2–10), biochar dosages (1, 2, 3, and 4 ), and AO7 concentrations (10, 20, and 30 . The kinetic data were better fitted to the pseudo-second-order (PSO) equation (R2 = 0.964–0.997) than the pseudo-first-order (PFO) equation (R2 = 0.789–0.988). The Freundlich isotherm equation (R2 = 0.965–0.994) fitted the sorption equilibrium data better than the Langmuir equation (R2 = 0.788–0.987), suggesting AO7 sorption on heterogenous NGBC700. The maximum monolayer AO7 adsorption capacities of the NGBC700 were 14.3, 12.7, and 8.4 at 10, 25, and 40 °C, respectively. The column AO7 sorption capacity was 4.4. Fixed-bed AO7 sorption data were fitted to the Thomas and Yoon–Nelson column models. The NGBC700 efficiently removed AO7 from locally available dye-laden wastewater. NGBC700 was regenerated using different NaOH concentrations. Possible interactions contributing to AO7 sorption on NGBC700 include hydrogen bonding, electrostatic interactions, and π–π electron donor–acceptor attractions. The estimated total preparation cost of NGBC700 was US$ 6.02 kg−1. The developed sustainable NGBC700 is potentially cost-effective and environmentally friendly, and it utilizes waste (Napier grass) to eliminate fatal AO7 dye from aqueous media.

Facile synthesis of anthranilic acid based dual functionalized novel hyper cross-linked polymer for promising CO2 capture and efficient Cr3+ adsorption

A novel hyper cross-linked polymer of 2-Aminobenzoic acid (HCP-AA) is synthesized for the adsorption of Cr3+ and CO2. The Brunauer–Emmett–Teller surface area of HCP-AA is 615 m2 g−1. HCP-AA of particle size 0.5 nm showed maximum adsorption of Cr3+ for lab prepared wastewater (93%) while it was 88% for real industrial wastewater. It is might be due to electrostatic interactions, cation-π interactions, lone pair interactions and cation exchange at pH 7; contact time of 8 min; adsorbent dose 0.8 g. The adsorption capacity was calculated 52.63 mg g−1 for chromium metal ions at optimum conditions. Freundlich isotherm studies R2 = 0.9273 value is the best fit and follows pseudo second order kinetic model (R2 = 0.979). The adsorption is found non-spontaneous and exothermic through thermodynamic calculations like Gibbs free energy (ΔG), enthalpy change (ΔH) and entropy change (ΔS) were 6.58 kJ mol−1, − 60.91 kJ mol−1 and − 45.79 kJ mol−1 K−1, respectively. The CO2 adsorption capacity of HCP-AA is 1.39 mmol/g with quantity of 31.1 cm3/g (6.1 wt%) at 273Kwhile at 298 K adsorption capacity is 1.12 mmol/g with quantity 25.2 cm3/g (5 wt%). Overall, study suggests that carboxyl (–COOH) and amino (–NH2) groups may be actively enhancing the adsorption capacity of HCP-AA for Cr3+ and CO2.

Maize leaves as a precursor for the synthesis of greened silver nanocomposite and nanoparticles

This study is aimed at the synthesis of nanoparticles (NPs) and nanocomposite (NC) using maize leave as precursor. Silver NPs (AgNPs) and AgNCs were synthesized from silver nitrate and maize leave extract using green approach. The maize leave NPs (AgNPs) and the maize leave NCs (AgNCs) were characterized using Fourier Transform infrared (FTIR), scanning electron microscopy (SEM), energy dispersion x-ray (EDX), Brunauer–Emmett–Teller (BET) surface area measurement, and dynamic light scattering (DLS) particle size analysis. The phytochemical analysis revealed the presence of tannin, oxalate, and flavonoids in appreciable quantity, which have proven to be a powerful reducing agent that facilitates the reduction of silver ions for the synthesis of silver NPs and silver nano composites. FTIR revealed that all the peaks identified in AgNPs and AgNCs belong to the characteristic bands of reducing compounds such as flavonoid compounds. The SEM-EDX results showed that the peaks observed from 2.9 to 3.1 Kev in the spectra indicate the presence of elemental silver as it is reduced from Ag+ to Ag. DLS analysis results showed that the average size and polydispersity index (PdI) of the synthesized AgNPs and AgNCs were 42.30 and 68.29 nm, 0.691 and 0.270, respectively. The single point BET surface area (m2/g) obtained for AgNPs and AgNCs were 223.3 and 209.5, respectively. The results showed maize leave as a potential precursor for the preparation of NPs and NCs.

Effect of covalently functionalized Indian bentonite clay on thermal, mechanical strength and morphology structure of extrusion/injection‐molded nylon 6 composites

AbstractThe research and development of functional polymer composites and their production have posed significant challenges, particularly in creating high mechanical strength and thermal stability composites. In this study, we utilized a micro corotation extruder and injection molding to produce covalently functionalized Indian bentonite clay‐nylon 6 high‐strength nanocomposites. For comparison, two different amines, 3‐aminopropyl trimethoxysilane and N‐[3‐(trimethoxysilyl) propyl] ethylene di‐amine, were used to functionalize bentonite clay. Additionally, 3% and 5% less amino clay filler was added in the nanocomposite to manufacture the polymer composite. Analytical techniques such as Powder X‐Ray Diffraction, Fourier transform infrared, thermal gravimetric analysis, and Brunauer–Emmett–Teller surface area were used to characterize the molecular orientation of amine functionalization on clay minerals. Wide‐angle X‐ray diffraction, atomic force microscopy, and transmission electron microscope were used to characterize the nylon 6 intercalated in amino clay nanocomposite and the polymer structure morphology. Thermogravimetric analysis and differential scanning calorimetry were used to investigate the crystalline thermal behavior of clay‐nylon 6 composites. From the results, it was observed that the composition containing 5 wt.% amino clay demonstrated a significant improvement in tensile strength when compared with the composition containing 3 wt.% amino clay. The mechanical strength and the thermal behavior showed a significant improvement of ⁓200% for 5% amino clay‐nylon 6 nanocomposite.

Metal-free adsorption and photodegradation methods for methylene blue dye removal using different reduction grades of graphene oxide

The release of organic pollutants and dyes into the environment by industries has had profound and harmful effects on both humans and ecosystems. Graphene oxide (GO) and its reduced form have been investigated for their effectiveness in removing pollutant dyes. GO nano-powder was synthesized using an improved version of Hummer’s method and subsequently thermally reduced at various temperatures, including 125, 150, 175, and 200°C, under vacuum conditions. In the X-ray diffraction spectra, an intense (002) diffraction peak was initially observed at 9.136° (2θ) for pristine GO. This peak gradually shifted towards higher angles as the reduction process took place and eventually disappeared when the GO was reduced at 200°C. The intensity ratio of the D and G bands (ID/IG ratio) for GO nano-powder in the Raman spectra decreased from 0.94 to 0.76 due to the reduction process. The FTIR spectra of GO and reduced graphene oxide (rGO) also illustrated the reduction process. The bandgap of pristine GO significantly decreased from 2.31 to 0.73 eV, as determined by ultraviolet-visible (UV−Vis) diffuse reflectance spectrophotometry during the reduction process. The surface area and pore volume of both pristine GO and rGO-150 were determined using the BET (Brunauer-Emmett-Teller) and BJH (Barrett-Joyner-Halenda) methods. The results indicated an increase in the BET surface area from 6.61 to 7.86 m2/g and a corresponding enhancement in pore volume from 0.118 to 0.128 cc/g after reduction. The adsorption and photocatalytic degradation behavior of pristine GO and reduced graphene oxides (rGOs) were examined using methylene blue dye. The pristine GO demonstrated impressive adsorption capability, effectively removing the dye by 85.78% within just 15 minutes and achieving nearly 97% removal after 4 hours. In contrast, the highest photocatalytic degradation of methylene blue, at 47.58%, was attained for the rGO sample reduced at 150 °C under the illumination of visible light.

Development of novel microporous guanazole complex for CO2 adsorption

A novel complex, resulting from the synthesis of a guanazole ligand coordinated with Zn(II), has been successfully synthesized through an environmentally friendly method and carefully characterized using a combination of analytical techniques, including Fourier-transform infrared (FT-IR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), N2 adsorption–desorption, scanning electron microscope (SEM), and X-ray photoelectron spectroscopy (XPS). The Brunauer–Emmett–Teller surface area of the guanazole complex is determined to be approximately 407.50 m2/g, featuring pore diameters and pore volume of 1.84 nm and 0.187 cm3/g, respectively. The emergence of micropores in the guanazole complex significantly enhances its CO2 adsorption capacity. The maximum CO2 adsorption capacity of the complex is observed to be 3.18, 2.08, and 1.51 mmol/g at temperatures of 273, 298, and 313 K, respectively. This study presents novel prospects for the controlled synthesis of nitrogen-rich complexes and their potential application in CO2 capture.

Lithium‐Lanthanide Heterometallic Organic Frameworks with Near‐Unity Photoluminescence Quantum Yields for Single‐Composition White‐Light Emission and Fluorescent Sensing on Nitrobenzene

AbstractLanthanide ion contained metal–organic frameworks (MOFs) have garnered significant attention in the fields of solid‐state lighting and chemical sensing due to their porous structure and distinctive optical properties. However, they also present challenges because of the limited photoluminescence (PL) intensity resulting from the parity‐forbidden f–f transitions of lanthanide ions. Herein, the study reports a new heterometallic MOFs Ln3Li2L4 (Li‐Ln‐MOF, Ln = Y, Eu, Tb and Dy, L = deprotonated 1,3,5‐tris(4‐carboxyphenyl)benzene) with a Brunauer‐Emmett‐Teller (BET) surface area of 774.1 m2/g. The porous crystal structure of Li‐Ln‐MOF is characterized by three kinds of channels interpenetrating with each other. By employing ligand alternation and lanthanide ion alloying strategies, Li‐Y1‐xEux‐MOF1 crystal isostructural with Li‐Ln‐MOF is synthesized by using 2,4,6‐tris(4‐carboxyphenyl)‐1,3,5‐triazine (H3TATB) as ligand. The Li‐Y0.7Eu0.3‐MOF1 crystal excels in the comprehensive performance with a BET surface area of 858.8 m2 g−1 and a near‐unity PL quantum yield. The time density functional theory and natural transition orbitals calculations unravel that the outstanding optical properties Li‐Y0.7Eu0.3‐MOF1 originates from the charge transfer between TATB3− and Eu3+. Benefiting from the excellent comprehensive performance of Li‐Y1‐xEux‐MOF1, the study reveals their potentials as single‐composition white‐light emission and fluorescent sensing probe for the detection of nitrobenzene.

Rapid synthesis of metal-organic framework CALF-20 in H2O/methanol solution under room temperature and normal pressure

In this study, a new process to synthesize Calgary framework 20 (CALF-20), a zinc-based metal-organic framework (MOF), in a H2O/methanol solution was developed, exhibiting a high CO2 adsorption capacity. Generally, CALF-20 was synthesized by a solvothermal method, requiring the consumption of considerable thermal energy. On the other hand, the proposed synthetic process required only 6 min to crystallize CALF-20 in a H2O/methanol mixed solution at room temperature (298 K) and normal pressure (101.3 kPa). In addition, CALF-20 was obtained in 93.3 % yield using zinc and oxalate sources under an aging time of 120 min. As-synthesized CALF-20 exhibited a Brunauer–Emmett–Teller surface area of 520 m2 g−1, a micropore volume of 0.19 cm3 g−1, a CO2 uptake of 3.84 mmol g−1 at 298 K, and a PCO2 of 100 kPa; these values were similar to those obtained for CALF-20 synthesized by the solvothermal method using high thermal energy. Furthermore, CALF-20 was crystallized without washing using H2O.The key factor for the crystallization of the CALF-20 structure in this process was the deprotonation of 1,2,4-triazole, which was caused by the acetate anion derived from zinc acetate as the starting metal source.

Removal of 2,4-dichlorophenoxyacetic acid through nitrogen doped modified palm kernel shell from aqueous solutions

The 2,4-Dichlorophenoxyacetic acid (2,4-D) is extensively used herbicide to boost crop productivity by reducing weed and pest infestation in agricultural fields. Due to the high solubility, mobility and low biodegradability, the ubiquitous presence of 2,4-D in the soil, surface and underground water has become serious threat for environment and human health.The present study addresses removal of hazardous 2,4-D by melamine-modified palm kernel shell biochar. A thorough examination was carried out, encompassing proximate analysis, elemental analysis, X-Ray Diffraction (XRD), Fourier-Transform Infrared Spectroscopy (FTIR), Brunauer-Emmett-Teller (BET) analysis, particle size distribution assessment, SEM (Scanning Electron Microscopy), and TEM (Transmission Electron Microscopy). Additionally, a comparative analysis was conducted, comparing palm kernel shell powder with biochar activated by KOH. The melamine-modified biochar (PKS-BM) exhibited notable characteristics, including nitrogen composition of 4.2 %, enhanced surface groups, a BET surface area 794.70 m2/g, total pore volume 0.449 cm3/g, particle size of 1400 nm, and 85 % removal of 2,4-D. Adsorption kinetics were accurately described by both pseudo-second-order model. According to the Langmuir model, the adsorption process was favorable, demonstrating a maximum adsorption capacity 990.10 mg/g. Enthalpy, entropy, and Gibbs free energy were computed from adsorption data, revealing exothermic and thermodynamically spontaneous 2,4-D adsorption on PKS-BM. These findings confirm the suitability of the synthesized melamine-impregnated palm kernel shell biochar to be used as adsorbent for removal of toxic herbicide from contaminated water.

Cobalt molybdate nanoflowers decorated bio-waste derived porous activated carbon nanocomposite: A high performance electrode material for supercapacitors

In this work, we report a supercapacitor electrode material based on nano-flower like cobalt molybdate decorated on porous activated carbon derived from waste onion peels (β-CoMoO4-POAC). The obtained POAC exhibits highly porous structure and after the hydrothermal treatment with salts of cobalt and molybdenum, we observed a uniform distribution of β-cobalt molybdate (β-CoMoO4) as nano-flowers on the surface of POAC. The chemical composition, morphology and porosity of the materials were thoroughly analyzed using field emission scanning electron microscopy, X-ray photoelectron spectroscopy, X-ray diffraction, infrared spectroscopy and Brunauer–Emmet–Teller surface area measurement. Due to its flower like and highly porous morphology, β-CoMoO4@POAC exhibits a high specific capacitance of 1110.72 F/g at a current density of 1 mA/cm2 with superior cyclic retention of 96.03% after 2000 cycles. The best electrochemical performance exhibited by β-CoMoO4@POAC is mainly due to its high surface area and porous nature of the material which assists in active transport of ions. This study reveals the exceptional electrochemical properties of β-CoMoO4@POAC which could be considered as a potential material for advanced energy storage devices.

Environmental-related applications of ZnO nanopowders: Photocatalytic activity and photoluminescence response to ethanol

Zinc oxide (ZnO) and copper-doped zinc oxide (ZnO:Cu) nanopowders were synthesized via solvothermal methods using methanol and hexamethylenetetramine (HMTA). Undoped ZnO nanopowders underwent calcination in O2-rich and H2-rich atmospheres at 600 °C. Samples were studied by scanning electron microscopy, Brunauer–Emmett–Teller (BET) surface area analysis, X-ray diffraction (XRD), and Raman, photoluminescence (PL) and UV–vis absorbance spectroscopies. The doping and calcinations led to a reduction of the optical bandgap of the nanopowders, while their structure remained hexagonal wurtzite with some changes in lattice parameters and average nanoparticle sizes. The Cu2+ doping led to a BET surface area and violet PL component increase. Samples were also examined for environmental related applications, namely as photocatalyzers for dye degradation and as ethanol optical sensors. For photocatalytic activity in methylene blue degradation under UV, H2-rich calcined powders excelled, with a rate constant of −0.076 min−1, surpassing −0.057 min−1 (ZnO:Cu), −0.056 min−1 (O2-rich calcination), and −0.041 min−1 (as-grown ZnO). We propose that this improvement can be attributed to the formation of ZnO/Zn interfaces stemming from the reduction of surface interstitial zinc by H2 during calcination, in addition to the observed reduction of the ZnO bandgap. The doped nanopowders PL also showed excellent response when exposed to ethanol vapor.

Preparation of self-standing ultra-thin three-dimensional covalent organic frameworks by interfacial polymerization for dye separation

Three-dimensional covalent organic frameworks (3D COFs) have garnered considerable attention in the adsorption of small molecules owing to their unique 3D pore structure and easily modifiable functional group sites. However, most 3D COFs exhibit lattice interpenetration, making the membrane fabrication process difficult. Most 3D COFs are prepared as powders using solvothermal methods, which severely limits their application in material separation. Therefore, self-supporting 3D COFs membranes were fabricated using room-temperature interfacial polymerization, a low-energy method. Traditional alkane/water interfacial polymerization methods have disadvantages such as poor water solubility of the monomer, volatile solvents, and low crystallinity. Herein, an imine-linked, self-standing, 3D COFs membrane with an ultrathin layer was engineered at the alkane/ionic liquid interface. Owing to the improved crystalline structure, which exposed a large number of imine-linked sites within a 3D pore channel, the constructed 3D COFs membrane exhibited a high Brunauer–Emmett–Teller surface area of 1061.4 m2·g−1 and high water flux of approximately 76 L·m−2 h−1 bar−1 and demonstrated excellent rejection rates of 97.76% and 95.36% for two cationic dyes, rhodamine B and methylene blue, respectively. The membrane exhibited high rejection rates after seven testing cycles. This study reveals the great potential of self-standing 3D COFs membranes as dye separation.

Synthesis and Characterization of a Photocatalytic Material from TiO2 Nanoparticles Supported on Zeolite Obtained from Ignimbrite Residue Used in Decolorization of Methyl Orange

In the present work, a TiO2/zeolite photocatalyst was synthesized by dispersing TiO2 nanoparticles obtained through the sol-gel method onto the surface of natural zeolite derived from ignimbrite residue. The zeolite was obtained from an ignimbrite rubble treatment collected from a quarry in Arequipa City, Peru. The research focused on the effect of zeolite on the TiO2 nanoparticles. The synthesized photocatalysts were characterized using various techniques, including field-emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray (EDS), X-ray diffraction (XRD), diffuse reflectance spectroscopy (DRS), and Brunauer–Emmett–Teller surface area analysis (BET). The results revealed that the TiO2/zeolite samples displayed high crystallinity, with TiO2 being present in three phases and zeolite being present in the analcime phase. Furthermore, these samples exhibited a band gap of 3.14 eV and a high surface area compared to that of bare TiO2. Finally, the photocatalytic activity of the TiO2/zeolite composite obtained was evaluated toward the decomposition of 10 ppm and 20 ppm of methyl orange (MO) dye. The TiO2/zeolite samples demonstrated improved photocatalytic activity compared to that of pristine TiO2 under the same experimental conditions. This enhancement is primarily attributed to the increased specific surface area of the TiO2/zeolite samples, making them promising materials for future efficient and sustainable photocatalytic applications.

Synthesis and Characterization of Enhanced Proton-Conducting Nafion<sup>® </sup>117- Silica Composite Membranes for Fuel Cell Applications

Nafion®/silica nanocomposite membranes were prepared by impregnation method from Nafion® 117 and sol-gel pre-synthesized n-octadecyl-trimethoxy silane (C18TMS) coated silica nanoparticles. The scanning electron microscope (SEM) of pristine silica particles displayed monodispersed nanospheres with diameters ranging from 150-350 nm; while Brunauer-Emmett-Teller (BET) analysis presented 760 m2/g BET surface area, a micropore-mesopore bimodal distribution of micropore systems with respective pore volume at 14.6 Å and 17.0 Å (2.01 x 10-3 cm3/g.Å), as well as the prolific mesopores centered at 29.5 Å (5.64 x 10-2 cm3/g.Å). Characterization of Nafion® 117 based membranes on SEM, Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and x-ray diffraction (XRD), and tensile stress exhibited varying surface morphology with silica loadings, structural interaction between membrane support and the ion exchanger, thermal stabilities (up to 330 °C), crystalline nature, and reasonable mechanical stability of nanocomposite membranes. The maximum water uptake (44.8 %) and proton conductivity of (1.14 x10-2 S/cm) were obtained on low Nafion®/SiO2 (5%) loaded membrane. While both composite membranes displayed the improved reduction in methanol permeability, 2.43x10-07 cm2/s at 80 °C was obtained with high Nafion®/SiO2 (10%) loading. Improved water uptake and proton conductivity substantiate the high ion exchange capacity (IEC) of 1.81 meq.g-1 when compared to IEC of 0.93 meq.g-1 [pristine Nafion®] and 1.46 meq.g-1 [Nafion®/SiO2 (10%)]. The increase in IEC value may be due to the high acid functionalization of additional sulfonic acid groups surrounded by hydrophilic segments of nanosilica, which improves the properties of the membrane. The high proton conductivity coupled with great water retention capabilities indicated that the Nafion®/SiO2 nanocomposite membranes could be utilized as proton exchange membranes for medium temperature methanol fuel cells. Keywords: Fuel cells; nanocomposite membrane; SiO2 nanofillers; methanol permeability; ion exchange capacity

Sol-gel synthesis of composite adsorbent coating from Prosopis juliflora–activated carbon for simultaneous adsorptive removal of Cd2+ and from wastewater

ABSTRACT To overcome the challenges associated with powdered activated carbon (PAC) in water and wastewater treatment, the efficacy of composite adsorbent coating (CAC) synthesized using a simple sol-gel method with Prosopis juliflora-activated carbon for the simultaneous reduction of Cd2+ and Cr2O72− was investigated. The CAC was characterized by FTIR (C-H, C = O, and O-H stretching), pHPZC (6 -6.6), SEM (porous-rough surface), and BET surface area (10.6 m2/g) techniques. Statistical analysis confirmed that pH and contact time significantly (p < 0.0001) affected both metal ions removal, with Cd2+ removal generally exceeding that of Cr2O72− due to better ionic properties. Using the optimized conditions (8.5 pH, 0.25 dosage, 5 mg concentration, 105 minutes contact time and 23.73 °C temperature), the predicted and experimental ion removal efficiencies were 86.86 and 83.98% for Cd2+ and 94.26 and 58.08% for Cr2O72−, respectively. The Langmuir adsorption isotherm was the best-suited model (R2 > 0.99), while the metal ions removal was regulated by the PSO kinetic model (R2 > 0.999). The adsorption process was endothermic and spontaneous, as indicated by thermodynamic values (−ΔG°, +ΔH°, +ΔS°). The study demonstrates CAC's effectiveness as an alternative to PAC, offering significant advantages in removing metal ions from wastewater.

Green synthesis of metal oxides (CaO-K2O) catalyst using golden apple snail shell and cultivated banana peel for production of biofuel from non-edible Jatropha Curcas oil (JCO) via a central composite design (CCD)

The use of biomass as a renewable, sustainable, and eco-friendly energy source is now widely recognized as a potential solution for a variety of environmental problems. To develop biodiesel production, cost-effective feedstocks such as agricultural waste, food waste, and non-edible/waste cooking oil were utilized. A heterogeneous solid base catalyst was synthesized by calcining a mixture of waste golden apple snail shell (Pomacea canaliculata) and cultivated (Musa sapientum) banana peel. In transesterification process, potassium oxide (K2O) derived from banana peel is used as a cocatalyst to improve the catalytic activity of calcium oxide (CaO) catalyst derived from waste shell. The innovative CaO-K2O catalyst was investigated by X-ray diffraction (XRD), X-ray fluorescence (XRF) and the Brunauer-Emmett-Teller (BET) technique. The morphology and elemental composition of calcium (Ca), potassium (K), and oxygen (O) in the catalyst were validated by field emission-scanning electron microscopy (FE-SEM) and energy dispersive X-ray spectroscopy (EDX). The CaO catalyst exhibited a BET surface area of 10.88 m2/g, which was enhanced to 14.62 m2/g upon combination with K2O. The Hammett indicator of CaO catalyst fell between 7.2 < H_< 9.8. However, the CaO-K2O catalyst exhibited a higher value of 15.0 < H_< 18.4, which could be attributed to the phase transition from CaO to CaO-K2O. To investigate the effects of catalyst concentration, ethanol/oil molar ratio, and transesterification time on the yield of fatty acid ethyl ester (FAEE). The optimal conditions for FAEE synthesis were determined using a central composite design (CCD) approach with response surface methodology (RSM). The regression equation obtained for the CCD model has a determination coefficient (R2) of 0.9921, indicating that this model is well-fitted. At 3.69 wt% catalyst concentration, 19.48:1 ethanol/oil molar ratio, and 1.80 h transesterification time, the highest FAEE yield from Jatropha Curcas oil (JCO) of 97.06 % was obtained. The novel catalyst has a strong yield and can be utilized for up to 6 cycles. It was found that the corresponding yield was 90 % when employing the same process parameters, demonstrating the high reusability of this catalyst. The biodiesel produced from non-edible JCO meets the criteria for standard biodiesel (ASTM D-6751 and EN 14214). The CaO-K2O catalyst is inexpensive, easy to make, biodegradable, recyclable, and environmentally friendly because it is derived from a biological residue. Because of these characteristics, it may be an appropriate candidate for the role of “green catalyst” in sustainable energy production.

Preparation of Metal - Organic Framework MIL-88B(Fe)-NH&lt;sub&gt;2&lt;/sub&gt; for Efficient Adsorption of Congo Red in Aqueous Environment

MIL-88B(Fe)-NH2 material was prepared by a simple solvothermal method. Various techniques were performed to investigate material characteristics including X-ray diffraction (XRD), scanning electron spectroscopy (SEM), transmission electron microscopy (TEM) and Brunauer-Emmett-Teller (BET) surface area. The result indicates that the particle shape is a bipyramidal hexagonal prism having a porous surface, and the BET surface area is 13.43 m2/g. Adsorption of congo red (CR) onto MIL-88B(Fe)-NH2 was studied as well. The adsorption equilibrium of the material is reached rapidly after 10 minutes with excellent adsorption efficiency (98.02%). Adsorption kinetic conforms to Langmuir isothermal adsorption model with the high maximum capacity of 333.33 mg/g.

Immobilization of Schiff base-Pd complex in mesoporous silica KIT-6 channels: A novel, green, recyclable, and highly versatile mesoporous catalyst for the carbon-carbon cross-coupling reaction

In this study, we developed an efficient and novel nanocatalyst by immobilizing Schiff base-Pd complex inside mesoporous silica KIT-6 channels, which were successfully synthesized by using a simple procedure. The catalytic activity of KIT-6@Schiff base-Pd was investigated in the synthesis of a wide variety of biphenyl derivatives. The N2 adsorption–desorption isotherms indicated the excellent Brunauer–Emmett–Teller surface area for KIT-6@Schiff base-Pd of 121.65 m2/g. The chemical and physical properties of raw and modified samples (KIT-6@Schiff base-Pd) were characterized based on Fourier transform-infrared spectra, thermogravimetric analysis, energy-dispersive X-ray spectroscopy, N2 adsorption–desorption, scanning electron microscopy, X-ray elemental mapping, and X-ray diffraction analyses. We found that the synthesized catalyst could be recovered and reused up to four times.

Low formaldehyde-emission particleboards with the addition of Scots pine wood waste derived activated carbon

ABSTRACT Free formaldehyde released after particleboard production poses significant risks to human and environmental health. This study investigated the impact of adding activated carbon produced from pine wood waste to particleboard on formaldehyde emissions to lessen this risk. In the first stage of the study, pine wood waste was activated with zinc chloride (ZnCl2) at 600°C for 90 min to produce activated carbon. The activated carbon was examined by scanning electron microscope, thermogravimetric analysis, Brunauer–Emmett–Teller (BET) analysis, fourier-transform infrared spectroscopy and X-ray diffraction. BET surface area of the produced activated carbon was 1102 m2/g. In the second stage of the study, activated carbons (0.5%, 1.0% and 1.5%) were added to a commercially preferred three-layer particleboard to enhance its mechanical, thermal and physical properties. In addition, the effects of the activated carbon on the free formaldehyde emissions of particleboard at 0 and 6 months were investigated. It was found that the free formaldehyde emissions of particleboards with activated carbon addition decreased by 24% at 0 months- and 6 months by 27% compared to the control group. Thus, waste material that has become a more valuable product as activated carbon will minimize harm to the environment and humans.

Removal of Fe3+ Ions from Aqueous Solutions by Adsorption on Natural Eco-Friendly Brazilian Palygorskites

This work focuses on the characterization of five palygorskite clays from the Brazilian state of Piaui and their feasibility as eco-friendly adsorbents for the removal of Fe3+ ions from aqueous solutions. For characterization, we applied the techniques of X-ray diffraction (XRD), X-ray fluorescence (XRF), scanning electron microscopy with energy dispersive spectroscopy (SEM/EDS), size distribution measurements, density measurement by He pycnometry, superconducting quantum interference device (SQUID) magnetometry, Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA/DTA), zeta potential measurement, hydrophobicity determination by contact angle, Brunauer–Emmett–Teller surface area analysis (BET technique) and atomic force microscopy (AFM). Batch experiments were performed in function of process parameters such as contact time and initial concentration of Fe3+. The natural palygorskites (Palys) had excellent performance for the removal of Fe3+ from aqueous solutions by adsorption (around 60 mg/g), and the Langmuir is supposedly the best model fitted the experimental data.