Moderate Surface Area Research Articles

Copper-based coordination polymer as a fast and efficient dye adsorbent from aqueous solutions

Green synthesis of a copper-based coordination polymer (Cu-CP) is reported utilizing a simple precipitation method. The prepared coordination polymer was characterized and used as a potent adsorbent for the elimination of organic dyes from aqueous solutions. The results of zeta potential analysis showed that the surface charge of the Cu-CP was −33.6 mV. In spite of negative surface charge and moderate specific surface area (99 m2·g−1), the prepared Cu-CP was a good adsorbent for removal of cationic e.g., malachite green (MG) and methylene blue (MB) as well as an anionic dye e.g., Congo red (CR). This efficiency could be attributed to π-π interaction and hydrogen bonding between adsorbent and adsorbate as the major forces leading to uptake of the dyes. However, MG with high removal efficiency (85.44%) at 2 min was chosen as a targeted dye for further consideration. Then, the effect of various parameters for adsorption of the MG e.g., adsorbent amount, pH, and initial concentration of dye were optimized. The adsorption isotherm and kinetic model for MG adsorption were also investigated. Finally, the adsorbent was reused after recycling which indicated high MG removal efficiency in successive tests.

Cascade upgrading of bio-based 4’-methoxypropiophenone to anethole enabled by hot-compressed alcohol over a Hf-phytic acid coordination catalyst

Hot compressed solvents (alcohol, water) have been widely used in the production of value-added chemicals from biomass due to their sufficiently low viscosity, high diffusivity, and environmentally-benign features. Anethole (AN) is a unique kind of natural aromatic compound, while its green synthesis method still requires to be explored. Herein, a novel porous acid-base bifunctional phytic acid (PA)-hafnium (Hf)(1:2.5) catalyst was prepared by a simple assembly of PA with Hf under a one-pot hydrothermal method (120 °C, 24 h). The PA-Hf(1: 2.5) possessed outstanding catalytic activity for the synthesis of AN from 4’-methoxypropiophenone (4-MOPP) at 220 °C and 15 bar in 2-pentanol (4-MOPP conversion: 99.8%, AN yield: 98.8%), which can be ascribed to its moderate surface area (95.3 m2/g), pore volume (0.18 cm3/g), mesopores (4.0 nm), and acid-base couple sites (density: 3.6 vs 1.7 mmol/g). 2-Pentanol was determined to serve as the superior hydrogen donor and solvent for the overall conversion process, which can remarkably hinder side reactions in this hot-compressed medium. Moreover, the cooperative interaction of Lewis acid-base couple sites (Hf4+-O2−) and Brønsted acidic species (-OH) of PA-Hf(1:2.5) led to its excellent catalytic performance. PA-Hf(1:2.5) was highly reusable with constant activity after five reaction cycles.

Synthesis of Hexa-Aminated Trinaphtho[3.3.3]propellane and Its Porous Polymer Solids with Alkane Adsorption Properties

Abstract Rigid three-dimensional π-skeletons are useful building blocks for organic porous materials but only a few types of compounds are available as compared with a variety of planar building blocks. Herein, we report that hexa-aminated trinaphtho[3.3.3]propellane was readily prepared by a two-step reaction sequence from a non-functionalized propellane in moderate yield and was active toward condensation with boronic acids and aldehydes. Solvothermal condensation with terephthalaldehyde gave an amorphous polymeric solid with moderate BET surface area, different from precursor molecules. The solid displayed good adsorption capacities for hydrocarbon gases and vapors. Because of multiple CH/π interactions, the adsorption was efficient even at low-pressure for n-butane and larger alkanes, providing good selectivity over smaller alkanes.

Acetylcholinesterase Biosensor Based on Functionalized Renewable Carbon Platform for Detection of Carbaryl in Food.

Enzymatic electrochemical biosensors play an important role in the agri-food sector due to the need to develop sustainable, low-cost, and easy-to-use analytical devices. Such biosensors can be used to monitor pathogens, endocrine disruptors, and pesticides, such as carbaryl, widely used in many crops. The use of renewable carbon (RC) sources, provided from biomass pyrolysis has been often applied in the fabrication of such sensors. This material is a great candidate for biosensor fabrication due to the presence of surface functional groups, porosity, and moderate surface area. This work describes the functionalization of RC material through an acid treatment with a sulfonitric solution HNO3/H2SO4 (1:3) and the resulting material was characterized by scanning electron microscopy. The obtained RC functionalized (RCF) and the acetylcholinesterase enzyme (AChE) were applied in the construction of the electrochemical biosensor on glassy carbon (GC) electrode and used to detect carbaryl in apple samples. The GC/RCF/AChE biosensor was able to detect the carbaryl pesticide from 5.0 to 30.0 nmol L−1, displaying a LOD of 4.5 nmol L−1. The detection of carbaryl in apple samples presented recoveries between 102.5 to 118.6% through the standard addition method. The proposed biosensor is a promising renewable tool for food safety.

Highly Efficient Iodine Capture and CO2 Adsorption using a Triazine‐Based Conjugated Microporous Polymers

AbstractTriazine‐based conjugated microporous polymers (CMPs) are a class of promising materials for adsorptive separation of CO2, which could be an effective alternative to chemisorption based approaches. Three novel CMPs were synthesized based on mixed building‐block approach under ionothermal conditions (ZnCl2, 400 °C). CMP@1‐3 possess moderate BET surface area of 325–707 m2 g−1. These polymers have a permanent porous structure, plenty of nitrogen atoms in the skeletons as effective sorption sites, and display a high adsorption performance for CO2 and iodine. Among them, CMP@3 displays outstanding CO2 adsorption capacity with uptake up to 120.8 cm3 g−1 at 1 bar and 273 K. In addition, CMP@3 exhibits a superior iodine uptake up to 308 wt.%. After adsorption and release, the structure of CMPs materials does not change and has high stability, which can be used as a convenient, economic and environmentally friendly material to develop its application in the field of I2 adsorption.

A powerful and multifunctional catalyst for organic synthesis, transformation, and environmental remediation: A polyImidazole supported trimetallic catalyst

We have constructed a state-of-the-art polyimidazole-supported trimetallic composite, PIm/FeᴖZnᴖAg, for organic synthesis, transformation, and environmental remediation on a single platform. The sustainable chemistry of organic reactions involving three-component coupling, CO2 insertion, [3 + 2]-click, Knoevenagel condensation, and CO2 cycloaddition reactions, and environmental pollutant reduction and bacterial inhibition are performed to comprehensively evaluate the power of this multifunctional catalyst. Most reactions withstand good functional group tolerance, producing forty-one derivatives with molecularly distinct moieties at good to near-quantitative yields under benign reaction conditions. Full chemical, microscopic, and structural characterizations reveal that metallic Ag, ZnO, and Fe2O3 with well-defined nanostructures are well interspersed and integrated on the PIm support. The metallic centers provide a conjugated multivalent architecture that work synergistically on a platform with moderate surface area and good CO2 adsorption capacity is the key to the multi-functionalities and effectiveness of PIm/FeᴖZnᴖAg, which is a current demand for developing green sustainable heterogeneous catalysts.

In-situ migration of Ni induced crystallization to boost the initial coulombic efficiency of nano Si anode for lithium ion batteries

Silicon (Si) has attracted enormous attention as next-generation anode material for lithium-ion batteries (LIBs) because of its ultra-high capacity. However, the practical application of Si is limited by its low initial coulombic efficiency (ICE) and unstable cycle performance. Here, a Ni-doped highly crystalline porous Si (Ni–CPSi) was prepared through facile magnesiothermic reduction and acid treatment. The enhanced crystallinity of Si effectively decreases the structural defects and suppresses the adverse side reactions. With moderate surface area and porous structure, the side reactions and volumetric expansion of Si during cycling are mitigated. Ni doping in Si crystal lattice further contributes to the enhancement of overall conductivity. As a result, the synthesized Ni–CPSi delivers a high ICE of 83.59%, and a superb rate capability of 682.8 mAh g−1 at 8.4 A g−1. In addition, Ni–CPSi anode achieves ultralong cycle life of 904.5 mAh g−1 at 4.2 A g−1 after 1000 cycles.

Green Synthesis of Magnetite-Based Catalysts for Solar-Assisted Catalytic Wet Peroxide Oxidation

A novel synthesis method under green philosophy for the preparation of some magnetite-based catalysts (MBCs) is presented. The synthesis was carried out in aqueous media (i.e., absence of organic solvents) at room temperature with recovery of excess reactants. Terephthalic acid (H2BDC) was used to drive the synthesis route towards magnetite. Accordingly, bare magnetite (Fe3O4) and some hybrid magnetite-carbon composites were prepared (Fe3O4-G, Fe3O4-GO, and Fe3O4-AC). Graphene (G), graphene oxide (GO), and activated carbon (AC) were used as starting carbon materials. The recovered H2BDC and the as-synthetized MBCs were fully characterized by XRD, FTIR, Raman spectroscopy, XPS, SQUID magnetometry, TGA-DTA-MS, elemental analysis, and N2-adsorption-desorption isotherms. The recovered H2BDC was of purity high enough to be reused in the synthesis of MBCs. All the catalysts obtained presented the typical crystalline phase of magnetite nanoparticles, moderate surface area (63–337 m2 g−1), and magnetic properties that allowed their easy separation from aqueous media by an external magnet (magnetization saturation = 25–80 emu g−1). The MBCs were tested in catalytic wet peroxide oxidation (CWPO) of an aqueous solution of metoprolol tartrate (MTP) under simulated solar radiation. The Fe3O4-AC materials showed the best catalytic performance among the prepared MBCs, with MTP and total organic carbon (TOC) removals higher than 90% and 20%, respectively, after 3 h of treatment. This catalyst was fairly successfully reused in nine consecutive runs, though minor loss of activity was observed, likely due to the accumulation of organic compounds on the porous structure of the activated carbon and/or partial oxidation of surface Fe2+ sites.

Role of Sporopollenin Shell Interfacial Properties in Protein Adsorption.

Sporopollenin shells isolated from natural pollen grains have received attention in translational and applied research in diverse fields of drug delivery, vaccine delivery, and wastewater remediation. However, little is known about the sporopollenin shell's potential as an adsorbent. Herein, we have isolated sporopollenin shells from four structurally diverse pollen species, black walnut, marsh elder, mugwort, and silver birch, to study protein adsorption onto sporopollenin shells. We investigated three major interfacial properties, surface area, surface functional groups, and surface charge, to elucidate the mechanism of protein adsorption onto sporopollenin shells. We showed that sporopollenin shells have a moderate specific surface area (<12 m2/g). Phosphoric acid and potassium hydroxide treatments that were used to isolate sporopollenin shells from natural pollen grains also result in the functionalization of sporopollenin shell surfaces with ionizable groups of carboxylic acid and carboxylate salt. As a result, sporopollenin shells exhibit a negative ζ potential in the range of -75 to -82 mV at pH 10 when dispersed in water. The ζ potentials of sporopollenin shells remain negative in the pH range of 2.5-11, with the absolute value of ζ potential showing a decrease with the decrease in pH. The negative surface charge promotes the adsorption of protein onto the sporopollenin shell via electrostatic interaction. Despite having a moderate surface area, sporopollenin shells adsorb a significant amount of lysozyme (145-340 μg lysozyme per mg of sporopollenin shells). Lysozyme adsorption onto sporopollenin shells alters the surface, and the surface charge becomes positive at acidic pH. Overall, this study demonstrates the potential of sporopollenin shells to adsorb proteins, highlights the critical role of sporopollenin shell's interfacial properties in protein adsorption, and identifies the mechanism of protein adsorption on sporopollenin shells.

Unlocking Zinc-Ion Energy Storage Performance of Onion-Like Carbon by Promoting Heteroatom Doping Strategy.

Onion-like carbon (OLC) is one kind of a quasi-nanosphere with a concentric graphite shell structure and abundant mesopores, which is appropriate for a high rate of charging/discharging and long-lifespan cycling. However, the moderate specific surface area seriously impeded its capacitance performance in comparison with activated carbon and porous carbon. Herein, we have unlocked the Zn ion storage performance of OLC material through introducing N and P dopants. Benefitting from the fabricated N,P-OLC with a fully accessible external surface area for ion adsorption, high proportion of mesopores for fast ion migration, and synergistic effect of N and P co-doping in a carbon matrix favoring chemical adsorption of Zn2+ ions, when applied as a cathode electrode for Zn ion hybrid supercapacitors (ZHSCs), such a device can deliver a high specific capacitance of 420.3 F g-1 (184.5 mA h g-1) at 0.5 A g-1, an outstanding capacitance retention capability of 262.7 F g-1 even at 20 A g-1 (∼63% capacitance retention), a high energy density of 149.5 W h kg-1, and a high power density of 26.7 kW kg-1. Furthermore, this N,P-OLC material can in situ tightly integrate with a carbon cloth (CC) or carbon fiber to construct a freestanding and flexible electrode. The fabricated Zn//N,P-OLC@CC device achieved a high energy density of 85.3 mW h cm-2, a high power density of 24.3 W cm-2, and a long-term cycling lifespan (77.8% after 50 000 cycles). At last, the assembled quasi-solid-state fiber-shaped ZHSCs also present excellent flexibility and practicality. Our study exhibits that OLC can act as a promising carbon electrode for ZHSCs.

Oxygen and nitrogen enriched pectin-derived micro-meso porous carbon for CO2 uptake.

Oxygen and nitrogen enriched micro–meso porous carbon powders have been prepared from pectin and melamine as oxygen and nitrogen containing organic precursors, respectively. The synthesis process has been performed following a solvothermal approach in an alkaline solution during which Pluronic F127 was added to the solution as the soft template. Following the solvothermal treatment, the carbonization process has been performed at 700, 850 and 950 °C. The synthesized porous carbons have been characterized by X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), nitrogen adsorption–desorption isotherms and Fourier transform infrared spectroscopy (FTIR). The surface area of 499.5 m2 g−1, total pore volume of 0.35 cm3 g−1, and a high nitrogen and oxygen content of 9.3 and 29.1 wt% are displayed for the fine sample. The optimal porous carbon had CO2 adsorption of up to 3.1 mmol g−1 at 273 K at 1 bar owing to abundant basic nitrogen-containing functionalities and the valuable micro–meso porous structure. Despite the absence of any reagent and also having a relatively moderate specific surface area, compared to similar materials, a very high ratio of adsorption capacity to specific surface area (6.2 μmol m−2) was observed. The Elovich kinetic model was found to be the best and the physisorption process was reported.

Fe3O4/graphene-oxide/chitosan hybrid aerogel based high performance supercapacitor: effect of aqueous electrolytes on storage capacity & cell stability

In this work, Fe3O4/graphene-oxide/chitosan aerogel (GCFA) with 3-D interconnected structure (average pore size ∼8.4 nm) and moderate BET surface area (∼59 m2/g) is synthesized by hydrothermal route. Three different hybrid symmetric supercapacitor cells are fabricated using GCFA as active electrode material, using basic (6M KOH: cell-1), acidic (1M H2SO4: cell-2), & neutral (Na2SO4: cell-3) as electrolyte mediums. Subsequently, a comprehensive study is carried out to assess the effect of electrolyte on the porous architecture, charge storage capacity, rate capability and cyclic stability. Besides, cell-3 also shows good cyclic stability with low initial fading (∼15%), good capacity retention (∼84%) It has been observed that cell-3 displayed better performance (specific capacitance ∼160 F g−1, specific energy∼14.6 Wh kg−1 and specific power∼0.77 kW kg−1) than either of cell-2 (∼160 F g−1, ∼7.84 Wh kg−1 and ∼0.45 kW kg−1) or cell-1 (∼102 F g−1, ∼1.54 Wh kg−1 and ∼0.14 kW kg−1) and excellent coulombic efficiency (∼91%) even after 10,000 charge-discharge cycles. This is attributed to the better pore accessibility, stability of residual surface functionalities under potential cycling, and least screening for intra-pore shuttling of counter-ions under neutral medium.

Moderate Specific Surface Areas Help Three-Dimensional Frameworks Achieve Dendrite-Free Potassium-Metal Anodes.

The inevitable problem of dendrites growth has hampered the further development of K metal anodes. Constructing a three-dimensional anode framework and potassiophilic nanocoating is an effective way to enlarge the specific surface area, reduce the local current density, and inhibit the formation of K dendrites. However, the effects of the electrochemically active surface area (ECSA) of the framework on deposition behavior have not been clarified. Hence, SnS2 nanosheets with different sizes are loaded on the surface of carbon paper (SnS2@CP) to improve the potassiophilicity and realize dendrite-free K-metal anodes. Experiments reveal that the size of SnS2 nanosheets would determine the ECSA of the framework, while the ECSA reveals the relative sizes of specific surface areas of frameworks. Excessive or limited specific surface areas will cause morphological collapse or weak potassiophilicity during potassiation, respectively, thus leading to high nucleation overpotential. The moderate specific surface area and abundant and stable potassiophilic sites prompt the SnS2@CP framework to achieve uniform electrodeposition of K. A low nucleation overpotential of 11.2 mV and a cycle life of more than 800 h are exhibited at a current density of 0.25 mA cm-2, indicating the directional strategy for stable and safe K metal anodes.

High-value products from ex-situ catalytic pyrolysis of polypropylene waste using iron-based catalysts: the influence of support materials.

Catalytic pyrolysis is considered a promising strategy for the utilisation of plastic waste from the economic and environmental perspectives. As such, the supporting materials play a critical role in the properties of the catalyst. This study clarified this influence on the dispersion of the iron (Fe) within an experimental context. Four different types of typical supports with different physical structures were introduced and explored in a two-stage fixed-bed reactor; these included metallic oxides (Al2O3, TiO2), a non-metallic oxide (SiO2), and molecular sieves (ZSM-5). The results show that the liquid products were converted into carbon deposits and lighter gaseous products, such as hydrogen. The Al2O3-supported catalyst with a relatively moderate specific surface areas and average pore diameter exhibited improved metal distribution with higher catalytic activity. In comparison, the relatively low specific surface areas of TiO2 and small average pore diameters of ZSM-5 had a negative impact on metal distribution and the subsequent catalytic reformation process; this was because of the inadequate reaction during the catalytic process. The Fe/Al2O3 catalyst produced a higher yield of carbon deposits (30.2wt%), including over 65% high-value carbon nanotubes (CNTs) and hydrogen content (58.7vol%). Additionally, more dispersive and uniform CNTs were obtained from the Fe/SiO2 catalyst. The Fe/TiO2 catalyst promoted the formation of carbon fibre twisted like fried dough twist. Notably, there was interesting correspondence between the size of the reduced Fe nanoparticles and the product distribution. Within certain limits, the smaller Fe particle size facilitates the catalytic activity. The smaller and better dispersed Fe particles over the support materials were observed to be essential for hydrocarbon cracking and the subsequent formation of carbon deposits. The findings from this study may provide specific guidance for the preparation of different forms of carbon materials.

Improving the Electrochemical Performances of Supercapacitors through Modification of the Particle Size Distribution of the Carbon Electrode

The effect of a synergetic mixture of large and small activated carbon composite particles on the performance of organic electrolyte-based EDLCs was examined in this work. Different surface areas, pore volumes, particle size distributions, and concentrations of surface functional groups were observed in bi-modal particle sizes of activated carbon composites. Using galvanostatic cycling, the cell capacitance of an activated carbon composite rose with an increase in the fraction of big particles (C8) over a wide range of rates. Due to their moderate specific surface areas, a relatively low fraction of smaller particle size, low concentration of oxygen functional groups, low contact resistance, and high ionic conductivity, the 0.25C4+0.75C8 carbon electrode composite has a high specific capacitance, high retention of high rate discharge, and long cycle life when compared to other composites and single carbon electrodes (C4, C8, and C12). The leakage current and gas evolution may be suppressed to an operating voltage of 3.0 V with an appropriate fraction of large and small particle composition on the carbon electrode, boosting the carbon cells’ reliability and stability.

N, O co-doped porous carbon with rich pseudocapacitive groups exhibiting superior energy density in an acidic 2.4 V Li2SO4 electrolyte

Designing a carbon material with a unique composition and surface functional groups for offering high specific capacity in a wide voltage window is of great significance to improve the energy density for the supercapacitor in a cheap and eco-friendly aqueous electrolyte. Herein, we develop an efficient strategy to synthesize a N, O co-doped hierarchically porous carbon (NODPC-1.0) with moderate specific surface area and pore volume as well as rich heteroatoms using a deep eutectic solvent (DES) as an activator. It is found that NODPC-1.0 with a large proportion of pseudocapacitive functional groups (pyrrole-N, pyridine-N and carbonyl-quinone) can work stable in an acidic 2 mol/L Li2SO4 (pH 2.5) electrolyte, exhibiting specific capacities of 375 and 186 F/g at the current densities of 1.0 and 100 A/g, respectively. Also, the assembled symmetric capacitor using the NODPC-1.0 as the active material and 2 mol/L acidic Li2SO4 (pH 2.5) as the electrolyte shows an outstanding energy density of 74.4 Wh/kg at a high power density of 1.44 kW/kg under a broad voltage window (2.4 V). Relevant comparative experiments indicate that H+ of the acidic aqueous electrolyte plays a crucial part in enhancement the specific capacity, and the abundant pseudocapacitive functional groups on the surface of the NODPC-1.0 sample play the key role in the improvement of electrochemical cycle stability under a broad voltage window.

The preparations of nanoporous carbon with multi-heteroatoms co-doping from black liquor powders for supercapacitors

Abstract A green and economically viable route without any additional activation agents and templates has been developed to synthesize biomass-derived nanoporous carbon for superior electric double-layer capacitors via direct pyrolysis of dried black liquor powders, which is the main waste in pulping and paper-making industry. The resulting carbon materials present hierarchical porosity and moderate specific surface area of 1134 m 2 g − 1 {\text{m}^{2}}\hspace{0.1667em}{\text{g}^{-1}} , as well as multi-heteroatoms co-doping such as N, S, Na and K, which exist originally in black liquor. When evaluated as electrode materials for supercapacitors in 6 M KOH aqueous electrolyte, the-prepared carbon samples deliver a significantly high gravimetric capacitance of 331 F g − 1 \text{F}\hspace{0.1667em}{\text{g}^{-1}} at 0.5 A g − 1 \text{A}\hspace{0.1667em}{\text{g}^{-1}} in a three-electrode system. Moreover, the fabricated symmetric supercapacitor also possesses a gravimetric capacitance of 211 F g − 1 \text{F}\hspace{0.1667em}{\text{g}^{-1}} at 0.5 A g − 1 \text{A}\hspace{0.1667em}{\text{g}^{-1}} , with an impressive long-term cycling stability of 92 % capacitance retention after 3000 cycles. This work explores a suitable and scalable approach for mass production of high-performance electrode materials with industrial wastes on the base of cost-efficiency and environment-friendship.

High-density oxygen-enriched graphene hydrogels for symmetric supercapacitors with ultrahigh gravimetric and volumetric performance

The contradiction between the porous structure and density of graphene materials makes it unable to meet the dual requirements of the next generation supercapacitors for gravimetric capacitance and volumetric capacitance. Herein, we successfully synthesized high-density oxygen-enriched graphene hydrogels (HOGHs) by a one-step hydrothermal method using high concentration graphene oxide (GO) solution and trometamol as precursors. The as-prepared HOGHs samples present a dense 3D network structure and moderate specific surface areas, which leads to a high packing density. In addition, the HOGHs samples also contain abundant oxygen-containing functional groups and some nitrogen-containing functional groups. These heteroatomic functional groups can provide pseudocapacitance for the electrode materials. Therefore, the HOGH-140 based symmetric supercapacitor shows ultrahigh gravimetric and volumetric specific capacitance (325.7 F g−1, 377.8 F cm−3), excellent rate performance and cycling stability. Simultaneously, the symmetric binder-free supercapacitor exhibits high gravimetric specific energy density (11.3 Wh kg−1) and volumetric specific energy density (13.1 Wh L−1) in 6 M KOH, respectively. These outstanding properties make the material have a good application prospect in the field of compact energy storage devices.

Preparation and characterization of carbon black (CB) using heavy residue fraction of spent tyre pyrolysis oil

In the interest of utilisation of industrial waste products, this paper investigated the preparation and characterization of carbon black (CB) made via partial oxidation of a heavy residue fraction (HRF) of spent tyre pyrolysis oil in a drop tube furnace. The effect of process temperature, residence time (Rtime), and O2 concentration on the yield and quality (elemental composition, functional groups, morphology, thermal behavior, and surface area) of HRF-CB were determined using elemental analyzer (EA), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), thermogravimetric analyzer (TGA), and Brunauer-Emmett-Teller (BET) nitrogen adsorption/desorption technique. Higher temperatures led to higher yields (41–60%) and better quality of the resultant CB. Above 1150 °C, the CB samples were comparable with commercial CB products, with low ash (<0.1%), low volatile matter (<6.1%), moderate BET surface area (11–24.2 m2g−1), and high C contents (~94–99%). Quality was also improved as Rtime or O2 increased but at some sacrifice to the total yield. HRF-CB aggregates were morphologically complex, highly structured and had good thermal stability, which increased with increasing process temperature, Rtime and O2 concentration, respectively. Interestingly, the hydroxyl, carbonyl and carboxyl surface groups in the HRF-CB were higher (54 – 69%) than commercial products (0–59%) under all process conditions, which is a desirable trait for enhanced bonding and mechanical properties but typically introduced to commercial CB by secondary procedures. Given their comparable properties, CB from heavy residues of spent tyre pyrolysis oil may be a suitable replacement for commercial CBs used in rubber reinforcement.

Fabrication of ferrous tungstate with enhanced sonocatalytic performance for meloxicam removal

The composites ferrous tungstate (FeWO4) were fabricated as the sonocatalyst for degradation of meloxicam (MEL) in water. The composites are prepared carefully via hydrothermal reaction of sodium tungstate dehydrate and ferrous ammonium sulfate hexahydrate. The morphology of FeWO4 were controlled successfully, by adjusting the acidity of the reaction solution (pH = 5, 6, 7, 8, 9). Multiple characterization results revealed that the obtained FeWO4 shared the similar nano-microspheres structure, but with different BET surface area and energy gap. The sonocatalytic experiments showed that FeWO4 nanomaterials with various synthetic pH values had different sonocatalytic performance on degradation of meloxicam (MEL), and FeWO4 synthesized at pH 6 reaches maximum of 73.5% on degradation of MEL. This phenomenon was not only due to the moderate BET surface area (31.18 m2/g), moderate pore size distribution (10–30 nm) and moderate energy gap (1.73 eV) of FeWO4 nano-microspheres, ·OH and holes also played a key role in the removal of MEL. The obtained catalyst was proved to be stable enough after four cycles. Our study demonstrates a novel finding, not reported previously, that FeWO4 could be utilized as a promising sonocatalyst to degrade MEL by ultrasound-driven.