Amount Of Functional Groups Research Articles

Functionalized expanded graphite foam supported by PVDF skeleton for cationic dyes selectively separating and purifying

In order to fully utilize the advantages of expandable graphite (large specific surface area and porous structure), a solvent-free method was used to provide a supporting skeleton for expandable graphite through melting, bonding and solidification of polyvinylidene fluoride (PVDF). Based on its porous structure and enhanced mechanical stability, the formed PVDF/expandable graphite composite foam, amounts of functional groups were introduced throughout the foam (outside on the surface and inner side in the expandable graphite) by deposition of tannic acid (TA) and dopamine (DA), endowing it selective adsorption characteristics. The functioned foam exhibited excellent dynamic dye adsorption capacity by capturing dye molecules firmly through π-π interaction, hydrogen bonding, and charge attraction between the functional groups and dyes. Furthermore, with low zeta potential (-24.9 mV), the functional groups showed selective adsorption properties resulting in rapid separation of cationic dyes and anionic dyes. The functionalized PVDF/expandable graphite composite foam contact these two materials together in order to complement each other's advantages, showing a new research orientation for the treatment of different types of dyestuff wastewater.

Sphagnum moss and peat comparative study: Metal release, binding properties and antioxidant activity.

Peat is the main constituent of cultivation substrates and a precious non-renewable fossil material. Peatlands provide important ecosystem services and allow the absorption and storage of carbon. Protecting peatlands helps tackle climate change and contributes to biodiversity conservation. Due to its importance, it is necessary to implement strategies to reduce the use of peat, such as replacing it with biomass-based alternative growing media constituents, such as Sphagnum moss. In this study, we compared the metal release and binding properties at two different pH, antioxidant activity, and total phenolic content of peat and Sphagnum moss from the Tierra del Fuego (TdF) region of southern Patagonia. Levels of the elements were determined by inductively coupled plasma mass spectrometry (ICP-MS), while the types and amounts of functional groups were characterized and compared using Fourier transform infrared (FTIR) spectroscopy. The total phenol level and antioxidant capacity were assessed using the Folin-Ciocalteu method and 2,2-diphenyl-1-picrylhydrazyl test. There are generally higher concentrations of leachable elements in peat than in Sphagnum moss at pH = 2, except Cs, Rb, Ti, and Zr. In contrast, at pH = 5, levels of all leached elements are highest in Sphagnum moss. Sphagnum moss shows a higher metal adsorption capacity than peat, except for Be, Mn, Tl, and Zn. Finally, the results showed that both matrices contained similar total phenolic contents: 0.018 ± 0.011 mg gallic acid equivalent (GAE) per gram dry sample for peat and 0.020 ± 0.007 mg GAE g-1 for Sphagnum moss. Instead, Sphagnum moss extracts showed a significantly higher antioxidant activity [0.026 ± 0.028 mmol Trolox equivalents (TE) g-1] than that estimated in peat (0.009 ± 0.005 mmol TE g-1). Humic acids, carboxylic acids, and phenolic and lignin groups were identified as the functional groups that mainly determined the antioxidant activity of the Sphagnum moss compared to peat. The present study resulted in an advancement of knowledge of these materials for more thoughtful future use and possible replacements.

Rapid reactivation of long-term frozen preservation anammox granular sludge by biochar: Performance, mechanism and artificial neural network optimization

Anaerobic ammonia oxidation (Anammox) is an efficient nitrogen removal technology for wastewater, and has been successfully applied in practical wastewater treatment. The preservation and rapid reactivation of anammox bacteria (AnAOB) play an important role in the anammox application. Biochar has been widely used in the water treatment industry due to its stable structure, economic and environmental protection characteristics. Hence, this study used biochar to accelerate anammox granular sludge (AnGS) performance recovery after 60 d preservation under low-temperature frozen (−20 °C). The time of AnGS recovery in the group with biochar addition was shortened by 15 d than the natural recovery group. Meanwhile, biochar addition improved the shock loading resistance of the anammox system. EPS secretion, and the types and quantities of functional groups in EPS increased under biochar stimulation, especially tighter PN. The functional groups in biochar can act as electron shuttles during anammox process, accelerating the electron transfer rate. Biochar addition enhanced the relative abundance of AnAOB, especially Candidatus Brocadia. PICRUSt analysis indicated that biochar promoted key gene related to anammox process and accelerated the recovery of frozen sludge. In addition, the changes in effluent nitrogen removal efficiency were successfully predicted by artificial neural network modeling with R = 0.9895 and MSE = 0.0048. This result may provide a new technological idea for the rapid recovery of AnGS under long time frozen conditions.

Study on the evolution characteristics of molecular surface active sites of low-rank coal in low-temperature oxidation stage

Compared with other coal types of coal, low - metamorphic coal contains numerous active sites, making it susceptible to spontaneous combustion and posing significant risks during production, transportation, and storage. To further reveal the evolution characteristics and laws of low-rank coal's active sites during the process of low-temperature oxidation of coal (LTOC), X-ray photoelectron spectroscopy (XPS), 13C nuclear magnetic resonance (13C NMR), and Fourier transform infrared (FTIR) experiments were used to determine the basic structural parameters such as the valence state of non-carbon features, types of carbon elements in coal macromolecules, and structure and quantity of functional groups. Combined with molecular modelling software (GaussView 6.0) and macromolecular calculation software (Grimme-XTB), macromolecular models of coal at different temperature points were constructed, and the surface energy field distribution was calculated. The number and energy change information of chemical and physical adsorption sites of low-rank coal during heating were obtained. The results show that during the LTOC, the chemical adsorption sites such as aliphatic hydrocarbons (-CH3/-CH2) have higher reactivity and can be converted into oxygen-containing functional groups (-CHO, –OH, –COOH); the number of physical adsorption sites increased first and then decreased, and reached the maximum at 50 °C. Coal exhibited a higher affinity for O2 at this temperature. The peroxide (-C-O-O-H) undergoes thermal decomposition, leading to H2O and weight loss of coal. The –CO and –COO structures undergo decarboxylation to generate CO, CO2, and other gases. This study comprehensively revealed the evolution of active sites through two key coal oxygen processes, physical and chemical adsorption, based on the gradual temperature elevation of low-rank coal. This holds immense significance for improving and enriching the understanding of the mechanism of coal spontaneous combustion(CSC), preparing more targeted CSC inhibition, and formulating efficient fire prevention and extinguishing measures.

Multi-Modal Structure and Distribution Analysis of Functional Groups on Carbon Supports for Polymer-Electrolyte Fuel Cells

Although structures of the functional groups formed on the surface of the carbon supports and their distribution on/inside supports have crucial impacts on determining performance of the catalyst electrodes, understanding of the relationship between them remains unclear, because of limitation of experimental methods for quantitative analysis of them with high spatial resolution. It is well-known that functional groups of the catalyst supports affect chemical properties of the supports, such as, redox- and acid-base properties, hydrophobicity, and electronic interaction. Thus, they should have a great influence on various aspects those related to the performance of polymer electrolyte fuel cell (PEFC), such as the activity, mass transportability, and durability of the catalysts and catalyst layers, and manufacturing process of catalysts and catalyst layer. 1,2). Furthermore, recently, in addition to various conventional high-surface area carbon supports, such as, Vulcan and Ketjen black, accessible carbon supports with mesopores which can host Pt particles protects them from direct ionomer adsorption and allow proton and O2 to have reasonable access to Pt particles, have been attracting great attention for improving catalyst utilization, activity, mass transportability, and suppression of Pt dissolution 3-5). The relationship between structure variation of functional groups on various supports and electrode performances should be of interest. The major difficulty for analyzing the functional groups on carbon supports come from the structure complexity of carbon surface (as well as inner part of the carbon particles), inhomogeneous distribution of various functional groups produced in various chemical processes, and multi-component structure of catalyst electrodes with catalysts and ionomers. Against such background, in this study, we have developed a new experimental approach utilizing multi-modal analysis method with x-ray photoelectron spectroscopy (XPS), x-ray absorption spectroscopy (XAS), temperature-programmed-desorption mass spectroscopy (TPD-MS), vibrational spectroscopy, electron tomography (3D-TEM), and cryo transmission electron microscopy (cryo-TEM). By combining suitable experimental probes for each structural feature and each component in multi-component structures, and by analyzing in integrated manner, we are able to understand the complex structure of functional groups on and inside carbon supports. Here, we demonstrate an example of the analysis for Vulcan (VULCAN® XC72, Cabot Corporation) and Pt-supported Vulcan (TEC10V30E, Tanaka Kikinnzoku Kogyo K. K. ). Vulcan is a solid carbon support used for polymer electrolyte fuel cell catalysts. The sample was reduced for about 30 minutes in a 100% hydrogen atmosphere at room temperature. Hard x-ray photoelectron spectroscopy (HAXPES) using synchrotron radiation x-rays with x-ray energy of 8 keV (BL46XU at SPring-8) . Also soft X-ray XAS were performed on BL1N2 at Aichi SR . Figure 1 shows the C1s HAXPES spectrum and the C K-edge XANES spectrum acquired by total electron yield (TEY) method. HAXPES was normalized by the signal intensity of the C-C substrate components (sp2, sp3) of the support at 284.5 eV 6), whereas the C K-edge XANES is normalized by the signal intensity of the 2pz (π*) orbital extending perpendicular to the carbon hexagonal network plane of the C–C substrate component of the support at 285.2 eV 7, 8). The functional groups are clearly observed in both spectra and the signal intensity of the functional group of the Pt catalyst increased with respect to the support alone, indicating that the amount of functional group on the support increased due to the Pt loading process. By combining other experimental results and theoretical simulations, the relationship between structure properties and electrode performance can be discussed. Acknowledgement This work was conducted in FC-Platform project supported by the New Energy and Industrial Technology Development Organization (NEDO). References :1) E. Antolini, Applied Catalysis B: Environmental 88, 1 (2009)2) Y.-J. Wang, N. Zhao, B. Fang, H. Li, X. T. Bi, and H. Wang, Chem Rev 115, 3433 (2015)3)V. Yarlagadda, M. K. Carpenter, T. E. Moylan, R. S. Kukreja, R. Koestner, W. Gu, L. Thompson, and A. Kongkanand, ACS Energy Letters 3, 618 (2018)4)S. Ott, A. Orfanidi, H. Schmies, B. Anke, H. N. Nong, J. Hübner, U. Gernert, M. Gliech, M. Lerch and P. Strasser , Nature Mater., 19, 77 (2020)5)A. Kobayash, T. Fujii, C. Harada, E. Yasumoto, K. Takeda, K. Kakinuma, and M. Uchida, Acs Appl. Energy Mater. 4 2307 (2021)6) S. Kundu, Y. Wang, W. Xia, and M. Muhler, J. Phys. Chem. C, 112, 16869 (2008)7) Y. Murakami, Y. Ota, and T. Okada, Anal. Sci., 39, 67 (2023)8) C. L. Guillou, S. Bernard. F. de la Pena, and Y. L. Brech, Anal. Chem., 90, 8379 (2018) Figure 1

Advanced Fractionation of Kraft Lignin by Aqueous Hydrotropic Solutions

Lignin is an underutilized high-potential biopolymer that has been extensively studied over the past few decades. However, lignin still has drawbacks when compared with well-known petroleum-based equivalents, and the production of tailored lignin fractions is highly in demand. In this work, a new method for the fractionation of Lignoboost Kraft Lignin (LKL) is proposed by using two different hydrotropes: sodium xylenesulfonate (SXS) and sodium cumenesulfonate (SCS). The different fractions are obtained by sequentially decreasing the hydrotropic concentration with the addition of water. Four and three different fractions were retrieved from the use of SXS and SCS, respectively. The LKL and respective fractions were analysed, and compared by GPC, FTIR-ATR, 1H-NMR, 13C-NMR, 31P NMR, 2D HSQC and SEM. The fractions showed different molecular weights, polydispersity, and amount of functional groups. Our water-based lignin fractionation platform can potentially be combined with different lignin extraction and processing technologies, with the advantage of hydrotrope recycling.

Adsorption of Sr on electrochemical deconsolidation products of matrix graphite

With the development of high-temperature gas-cooled reactor (HTGR), the disposal of its spent fuel elements will become an important factor that affects its industrialization. As one of alternative routes for head-end process of HTGR spent fuels’ reprocessing, electrochemical deconsolidation method separates TRISO fuel particles from matrix graphite (MG) and produces electrochemical deconsolidation product (EDP) with larger surface area than MG and abundant functional groups. In this paper, the chemical composition and structure of EDPs obtained in HNO3 with concentrations of 4%, 34% and 68% were studied, and the application of EDPs on strontium ions (Sr2+) adsorption was investigated. The results showed that EDP-4% with more carbonyl groups on the surface possessed the largest Sr2+ capacity of 44.8 mg/g at pH 5, while EDP-34% containing more hydroxyl and epoxy groups had the smallest capacity of 9.6 mg/g. The capacity for EDP-68% lay in the mid value of 19.5 mg/g. Density functional theory (DFT) calculations and adsorption experiments jointly evidenced that the type and amount of functional groups both significantly impacted the Sr2+ adsorption. The proposed adsorption mechanism provides theoretical foundation to evaluate the distribution of 90Sr during HTGR spent fuels’ electrochemical deconsolidating.

Investigation of The Effect of Vacuum Drying Conditions On Graphene Oxide Production

Graphene consists of sp2 hybridized carbon (C) atoms arranged in a honeycomb shape as single layer. Graphene oxide (GO) structures have importance over graphene, because of hydrophobic nature of graphene, non-adjustable band gap, complex production processes and its production costs. GO structures are generally synthesized using graphite or carbon sources which are similar compounds compare to graphene. GO consists of both sp2 and sp3 hybridized C atoms to which functional groups are attached at the top and bottom of the layer. The mechanical, electronical and thermal properties of GO structures can be controlled during the production phase thanks to these oxygen-containing functional groups in their structure. These functional groups consist of oxygen (O) and hydrogen (H) elements in the form of carbonyl, hydroxyl, carboxyl or epoxide and they are highly dependent on the production method. Among the various methods for producing GO structures, the Hummers method stands out with its low cost, time efficiency and ease of parameter control. In this study, GO production was carried out by improved Hummers method, which consists of steps such as mixing with strong acids and oxidizing agents, washing with water and drying. The drying process, which is the last stage of production, directly affects the physical and chemical properties of the final product. Thus, the type and the amount of functional groups in the structure may change according to the drying method applied. In this study, the effect of drying, which is one of the Hummers method production parameters, on the oxidation level of the GO structure was investigated. For this purpose, GO structures were dried at different vacuum levels and atmospheric conditions. The produced GO structures were characterized using X-Ray Diffractometry (XRD) and Fourier Transform Infrared Spectroscopy (FTIR) devices. While XRD analysis showed the difference in phase structure, oxidation degree and interlayer distance between GO layers, FTIR analysis revealed the changes of functional groups in GO structures depending on drying conditions.

Magnetic Fluid Assisted Electro-Leaching for Metal Recovery

In current research, micro and nanoparticulate electrode materials have taken their place because they offer a large internal surface area with respect to the macroscopic dimensions of such electrodes [1]. The nano-impact method is a powerful tool that enables the characterization of individual particulate nano-objects in solution and study of their reactivity [2]. A three electrodes setup system working as a standard electrochemical cell is typically used. Magnetite (Fe3O4) nanoparticles with the strongest saturation magnetization of all naturally occurring iron oxides, combined with properties such as low toxicity, good biocompatibility, high stability, and low production costs, have attracted a lot of interest [3]. There is also substantial interest in their use as magnetic fluids, in data storage, in catalysis, and as electrode materials.In this work, magnetite micro and nanoparticles have been synthetized by chemical precipitation method in presence of surfactants or functional organic polymer. The effects of various parameters such as contact time, dosage of magnetite nanoparticles and the amount of functional groups on the adsorption capacity and efficiency of the treatment in the adsorption of copper and lithium are investigated. The use of surfactants to stabilize these synthesized nanoparticles is crucial, as Fe3O4 nanoparticles have high surface energies and tend to aggregate. Magnetic fluids constituted by dispersed functionalized magnetite particles are used as particulate electrode in different fluids and characterized into a three electrodes cell in order to evaluate their electrochemical behavior. A deeper understanding of the particulate electrode has been performed in situ on supported particles through electrochemical AFM/STM measurements, highlighting the behavior of the single aggregate. Together with the charge transfer characterization as a function of particles size and concentration, functionalization and fluid composition, practical applications of the particulate electrodes will be presented. Specifically, the use of particulate electrodes in the electrochemical metal recovery, showing the ions adsorption properties of magnetite particles as a function of surface functionalization and their electrochemical reduction at the magnetic fluid/current collector interphase will be discussed for specific systems, e.g. copper and lithium.1. V. Noack, H. Weller, A. Eychmu1ller, J. Phys. Chem. B, 106 (2002) 8514-85232. S.V Sokolov et al., Phys.Chem.Chem.Phys., 19 (2017) 283. K. Murugappan, ChemElectroChem, 1 (2014) 1211 – 1218

Machine learning model for understanding laser superhydrophobic surface functionalization

A general machine learning (ML) framework of surface wetting is proposed by considering a broad range of factors, including solid surface topography, solid surface chemistry, liquid properties, and environmental conditions. In particular, an XGBoost-based ML model is demonstrated for learning the surface wetting behaviors processed by a laser-based surface functionalization process, namely nanosecond laser-based high-throughput surface nanostructuring (nHSN). This is the first known attempt to apply machine learning to surface wetting by considering both surface topography and surface chemistry properties. Novel microscale and nanoscale topography parameters viz., roughness, fractal, entropy, feature periodicity are defined with suitable computer algorithms to comprehensively describe the surface topography. A novel set of surface chemistry parameters such as polarity, volume, and amount of functional groups are also used as the machine learning model input. Upon analyzing the importance of each parameter for the nHSN process, surface chemistry shows the greatest importance in determination of surface wettability, while surface morphology also plays a part in influencing the wettability. • A machine learning model is firstly proposed for surface wettability considering both topography and chemistry. • Fractal dimension, 2D-entropy, and periodicity are used to describe surface morphology. • Polarity and functional groups are used to describe surface chemistry. • The results showed that the surface chemistry is the dominant feature while surface topography plays a supportive role.

Assessment of structural protein expression by FTIR and biochemical assays as biomarkers of metabolites response in gastric and colon cancer

Colon and gastric cancers are the widespread benign types of cancers which are synchronous and metachronous neoplasms. In terms of the progression and progress of the disease, metabolic processes and differentiation in protein structures have an important role in for treatment of the disease. In this study we proposed to investigate the metabolic process and the differentiation of protein secondary structure among colon and gastric cancer as well as healthy controls using biochemistry and Fourier Transform InfraRed spectroscopy (FTIR) methods. For this purpose, we measured blood serum of 133 patients, which were conducted upon oncology department (45 colon cancer, 45 gastric cancer and 43 control individuals). The obtained spectroscopic results and biochemical assays showed significant reduction in the amount of functional groups in cancer groups contrary with total protein measurements and structure of protein differences between colon and gastric cancers. Differentiations were visible in serum levels of CEA, CA-125, CA-15-3, CA-19-9 AFP (Alpha fetoprotein) of gastric and colon cancer patients as well as in amide III and secondly described amide I regions. Our findings suggest that amide I bonds in colon cancer cells can be helpful in diagnosis of colon cancer. Indeed, our results showed that metabolic processes were higher in gastric cancer group than in colon cancer. Hence, FTIR spectroscopy and curve-fitting analysis of amide I profile can be successfully applied as tools for identifying quantitative and qualitative changes of proteins in human cancerous blood serum. However, what is very important, in PCA analysis we see, that the scatter plot of PC1 (variability 80%) and PC2 (variability 15%) show that the data related to the control and two cancer groups are clustered together with different magnitudes and directions.

A Strategy to Revalue a Wood Waste for Simultaneous Cadmium Removal and Wastewater Disinfection

In this investigation, the possibility of wood waste (hardwoods such as oaks’ and alternatives’ staves from Balkan cooperage) revalorization for simultaneous cadmium removal and wastewater disinfection was examined. All samples were characterized in terms of their crystallinity index and crystallite size, amount of functional groups, and surface chemistry (determined by ATR-FTIR) as well as antibacterial activity. Mulberry is characterized by the lowest crystallinity index which can be ascribed to the highest crystallite size disabling crystallite denser packaging, while myrobalan plum has about 23% lower crystallite size that enables crystallite better packaging, thus resulting in a 42.4% higher crystallinity index compared to the mulberry. All oaks have a significantly higher amount of carboxyl groups compared to the alternatives (0.23-0.28 vs. 0.12-0.19 mmol/g). The adsorption experiments revealed that with increasing the initial cadmium concentration from 15 up to 55 mg/g, samples’ adsorption capacity increases by 89-220%. The equilibrium data fit well with the Langmuir isotherm model implying monolayer coverage of cadmium ions over a homogeneous wood surface. The relationship between the samples’ maximum adsorption capacities (ranged from 5.726 to 12.618 mg/g), their crystallinity index, and crystallite size was established. According to ATR-FTIR spectra, aldehyde, carboxyl, hydroxyl, and phenyl groups present on the wood waste surface are involved in Cd2+ adsorption which proceeds via the interplay of the complexation, cation- π interactions, and ion-exchange mechanisms. Mulberry and myrobalan plum showed about 89% and 80% of the total uptake capacity of cadmium within 60 min, while the equilibrium was attained after 240 min of contact time. Good compliance with pseudo-second kinetic order indicated that cadmium adsorption was mediated by chemical forces. Thermodynamic parameters revealed the spontaneous and exothermic character of cadmium ion adsorption onto mulberry and myrobalan plum. All studied samples provide maximum bacterial reduction (>99%) for E. coli and S. aureus. Wood waste from Balkan cooperage can be successfully used for simultaneous cadmium removal and wastewater disinfection.

Effect of Functional Groups in Coal on the Depth of Adsorption Potential Well

Due to the complexity of the internal structure of natural coal and its characteristic of multicomponent, the depth of its methane adsorption potential well is nonuniform, which makes it difficult to accurately evaluate the adsorption capacity of coal. Besides, in order to find out the factors affecting the depth distribution of potential wells in natural coal, this paper calculated the depth and number of potential wells during methane adsorption in coal according to the Langmuir adsorption kinetics process. Coal samples with different metamorphic degrees were tested and analyzed by infrared spectroscopy diffraction technology. The relationship between the structural parameters of functional groups in coal samples with different metamorphic degrees and the distribution of different depths of adsorption potential wells in coal samples was studied. Some main conclusions are as follows: The number of adsorption potential wells at different depths in natural coal with different metamorphic degrees has multipeak distribution characteristics. With the increase of the metamorphic degree of coal sample, the structures such as aliphatic branched chain structure and oxygen-containing functional groups in coal structure break, fall off, and deoxygenate. The relative content of aliphatic hydrocarbons is significantly reduced and condensed into aromatic hydrocarbons and aromatic ring structures. The different types and quantities of functional groups on the surface of coal samples lead to different forces between coal molecules and methane gas molecules, thus affecting the distribution of different depths of adsorption potential wells in coal samples.

Comprehensive evaluation of adsorption performances of carbonaceous materials for sulfonamide antibiotics removal.

Sulfonamide antibiotics have highly toxic effects on humans and other organisms within the food chain. Adsorption by various carbonaceous materials is an effective method for removing them from the aqueous environment. Batch adsorption experiments were conducted between adsorbents and sulfamethoxazole (SMX) by studies of characterization, isotherm model, and kinetic model. The adsorption performances and mechanism of fifteen carbonaceous materials to remove SMX have been comprehensively evaluated. Results of the characterization showed that not only porosity, but also surface chemistry plays an important role in the adsorption process. Changes in the type and quantity of functional groups before and after adsorption are positive for the recyclability of carbonaceous materials. Moreover, kinetic studies showed that the adsorption process followed the pseudo-second-kinetic model and the intra-particle diffusion model. Four adsorbents (i.e., W-GAC, 3M-GAC, GP, and PAC) in this study have the best performance in each corresponding category in terms of the adsorption of SMX. Therefore, the results provide an indispensable reference for evaluating the adsorption performances of a variety of carbonaceous materials, and thus can support the selection of adsorbents for different applications. Graphical abstract.

Synthesis and comparison studies of activated carbons based folium cycas for ciprofloxacin adsorption

The comparison of activated carbons with bicarbonate as the activating agents for antibiotics adsorption have rarely been studied. In this study, the four samples were synthesized from low-cost and green raw material (folium cycas) by potassium bicarbonate or sodium bicarbonate activation with or without urea as the assist activating agent in one step. The product carbons were characterized by N2 adsorption/desorption isotherm, scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FT-IR), Boehm’s titration methods. The results show that potassium bicarbonate and urea are favorable for the development of pores and the formation of functional groups, carbon activated by potassium bicarbonate and urea (FPU-C) has the highest BET surface area and amounts of functional groups. Adsorption data of the four carbons for ciprofloxacin hydrochloride (CIP) were analyzed by four isotherm models (Langmuir, Freundlich, Temkin, and Dubinin–Radushkevich), indicating Langmuir and Temkin models were more suitable in expressing adsorption process. Compared with other carbons, FPU-C reflects more than 100% higher adsorption capacity for CIP. The maximum adsorption capacity attained 204.08 mg CIP per gram of FPU-C. The results suggest that potassium bicarbonate and urea as the weak base could play the role of activation mutually to acquire excellent activated carbon for CIP removal.

Reduced Graphene Oxide/Polymer Monolithic Materials for Selective CO2 Capture.

Polymer composite materials with hierarchical porous structure have been advancing in many different application fields due to excellent physico-chemical properties. However, their synthesis continues to be a highly energy-demanding and environmentally unfriendly process. This work reports a unique water based synthesis of monolithic 3D reduced graphene oxide (rGO) composite structures reinforced with poly(methyl methacrylate) polymer nanoparticles functionalized with epoxy functional groups. The method is based on reduction-induced self-assembly process performed at mild conditions. The textural properties and the surface chemistry of the monoliths were varied by changing the reaction conditions and quantity of added polymer to the structure. Moreover, the incorporation of the polymer into the structures improves the solvent resistance of the composites due to the formation of crosslinks between the polymer and the rGO. The monolithic composites were evaluated for selective capture of CO2. A balance between the specific surface area and the level of functionalization was found to be critical for obtaining high CO2 capacity and CO2/N2 selectivity. The polymer quantity affects the textural properties, thus lowering its amount the specific surface area and the amount of functional groups are higher. This affects positively the capacity for CO2 capture, thus, the maximum achieved was in the range 3.56–3.85 mmol/g at 1 atm and 25 °C.

Performance enhancement of catalytic bipolar membrane based on polysulfone single base membrane for electrodialysis

To avoid the bubbling of bipolar membrane (BPM) and improve its water dissociation performance, the same base membrane material polysulfone (PSF) was chosen and graphene oxide-polyvinyl alcohol (GO-PVA) system was introduced as an intermediate layer to prepare a new series of BPMs. The effects of anion exchange layer (AEL) and intermediate layer were fully investigated from the viewpoint of voltage-current curves and water dissociation ability tests. The results demonstrated that the amounts of functional groups in the AEL and hydrophilicity of intermediate layer had significant effects on the BPM performance, and the voltage drop, energy consumption and current efficiency could be greatly modified by adjusting the functionalized degree of AEL and the content of GO mixed in PVA solution. Moreover, it turned out that the prepared BPM based on PSF single base membrane had better stability in the long-term operation, laying an important foundation for subsequent research on performance enhancement of BPMs based on single base membrane material.

REMOVAL OF ORGANIC POLLUTANTS FROM WASTEWATER BY ACTIVATED CARBON PREPARED FROM DATES STONES OF SOUTHERN ALGERIA

The aim of this work is to prepare activated carbon from date seeds to treat wastewater. The study of the characteristics of activated carbon from El-Oued dates gave the following results: surface area (125.86m2/g), pore volume (0.039cc/g), pore size (16.25mm), microspores surface area (92.28 m2/g), the external surface (33.57 m2/g), methylene blue index (13.6 mg/g), iodine number (735.2 mg/g) and amount of functional groups (4.10-2 mol/g). The best conditions for the removal of organic pollutants are: contact time (5 min), stirring speed between 200 and 300 rpm and a pH below 5 or above 8. The removal of organic pollutants in wastewater from El-Oued region prepared by the charcoal has led to very significant abatement rate: COD (86.9%) and BOD5 (87.55%).

Kinetic and thermodynamic parameters guiding the localization of regioselectively modified kaolin platelets into a PS/PA6 co-continuous blend

This article highlights the role of kinetic and thermodynamic parameters on the localization of modified kaolin platelets into a high interfacial tension co-continuous PS/PA6 blend after extrusion, injection molding and annealing. Three kinds of copolymers were synthesized and grafted on kaolin: poly(styrene-co-(methacryloyloxy)methyl phosphonic acid) copolymer (P(S-co-MAPC1(OH)2)), polystyrene terminated 3-(mercaptopropyl)triethoxysilane, (ETS-PS) and poly(styrene-co-3-methacryloxypropyltrimethoxysilane) copolymer, (P(S-co-MPS)). Those copolymers were distinguished by (1) the nature of their functional groups (phosphonic acid that reacts only with aluminol groups or alkoxysilane that reacts with both silanol and aluminol groups), (2) the amount of functional groups and (3) their molecular weights. After functionalization the kaolin samples (K1, K2 and K3, respectively) were analyzed by FTIR, TGA and Py-GC/MS to evaluate the grafting. It was shown that P(S-co-MAPC1(OH)2) and P(S-co-MPS) copolymers grafted on kaolin led to highly anisotropic K1 and K3 kaolin platelets, respectively. Then, 50/50/5 PS/PA6/Ki samples (i = 0 to 3) were processed as follows: (1) kaolin platelets were dispersed (via solvent cast) into the PS phase. Then, (2) PS + kaolin were melt mixed by microcompounder with PA6, then (3) the PS/PA6/Ki were injection molded into disks and finally (4) they were annealed (via dynamic or quiescent annealing). Thanks to the high shear rate and longtime of mixing during extrusion (microcompounder), all the kaolin platelets (unmodified K, K1, K2 and K3) crossed the interface and were localized in the PA6 phase. All Ki kaolin stayed in the PA6 phase during injection. However, after annealing (quiescent or dynamic), the localization of the nanoplatelets was guided by thermodynamic parameters, and SEM analysis revealed the segregation of K1 and K3 kaolin platelets at the polymers interface, with a high tendency to impede polymer phases coalescence. Hence, modified K1 and K3 kaolin are promising compatibilizing agents for a co-continuous PS/PA6 blend.

Synthesis of oxygen functionalized carbon nanotubes and their application for selective catalytic reduction of NO x with NH3.

Oxygen functionalized carbon nanotubes synthesized by surface acid treatment were used to improve the dispersion properties of active materials for catalysis. Carbon nanotubes have gained attention as a support for active materials due to their high specific surface areas (400–700 m2 g−1) and chemical stability. However, the lack of surface functionality causes poor dispersion of active materials on carbon nanotube supports. In this study, oxygen functional groups were prepared on the surface of carbon nanotubes as anchoring sites for decoration with catalytic nanoparticles. The oxygen functional groups were prepared through a chemical acid treatment using sulfuric acid and nitric acid, and the amount of functional groups was controlled by the reaction time. Vanadium, tungsten, and titanium oxides as catalytic materials were dispersed using an impregnation method on the synthesized carbon nanotube surfaces. Due to the high density of oxygen functional groups, the catalytic nanoparticles were well dispersed and reduced in size on the surface of the carbon nanotube supports. The selective catalytic reduction catalyst with the oxygen functionalized carbon nanotube support exhibited enhanced NOx removal efficiency of over 90% at 350–380 °C which is the general operating temperature range of catalysis in power plants.