Reaction Characteristics of Hydrogen-Rich Syngas Production by Sludge/Coal Cogasification Based on the Iron-Based Oxygen Carriers

With the acceleration of industrialization and urbanization in China, wastewater treatment is increasing yearly. As a by-product of wastewater treatment, the gasification of sludge with coal in chemical looping process is a clean and efficient conversion technology. To explore the reaction behavior of cogasification of sludge and coal with iron-based oxygen carriers (OCs) for producing hydrogen-rich syngas, the experiment of cogasification using Fe2O3/Al2O3 as OC in a fluidized bed reactor was conducted. The result showed that the volume percentage of hydrogen (H2) and syngas yield is proportional to the amount of sludge added. The optimal operation conditions were: temperature at 900 °C, the mass ratio of OC to coal at 5.80 and mass ratio of sludge to coal at 0.2. Under this operating condition, the volume percentage of H2 and syngas yield in the flue gas was 75.6 vol% and 97.5 L·min-1·kg-1, respectively. Besides, the OC showed a stable reactivity in the sixth redox cycle with added sludge. However, the reactivity of OC significantly declined in the seventh and eighth redox cycles. It was recovered when the ash was separated. The decrease in the specific surface area of the OC caused by ash deposition is the main reason for the decline in its reactivity. The kinetic analysis showed that the random pore model describes the reaction mechanism of sludge/coal chemical looping gasification (CLG). The addition of sludge can reduce the activation energy of coal CLG reaction, accelerate the gasification reaction rate and increase the carbon conversion.

Trends on the Development of Hybrid Supercapacitor Electrodes from the Combination of Graphene and Polyaniline

The high demand for efficient energy devices leads to the rapid development of energy storage systems with excellent electrochemical properties, such as long life cycles, high cycling stability, and high power density. SC is postulated as a potential candidate to fulfill this demand. The combination of graphene and polyaniline can create SC electrodes with excellent electrical conductivity, high specific surface area, and high capacitance. The graphene/polyaniline hybrid electrodes represent an attractive means to overcome the major drawbacks of graphene or polyaniline non-hybrid (single) electrode materials. In this review article, the trend in the development of various graphene/polyaniline hybrid electrodes is summarized, which includes the zero-dimension graphene-quantum-dots/polyaniline hybrid, one-dimension graphene/polyaniline hybrid, two-dimension graphene/polyaniline hybrid, and three-dimension hydrogel-shaped graphene/polyaniline hybrid. Several strategies and approaches to enhance the capacitance value and cycling stability of graphene/polyaniline hybrid electrodes are discussed in this review article, such as the addition of transition metal oxides and metal-organic frameworks, and modification of graphene into functionalized-graphene. The performance of the electrodes prepared from the combination of graphene with other conducting polymers (i.e., polypyrrole, polythiophene, and polythiophene-derivatives) is also discussed.

Synthesis and Evaluation of Fluorinated Benzyl Ethers as Alternate Protecting Groups for Enhanced NMR Resolution in Oligosaccharide Synthesis

Oligosaccharides have been playing an important role in biological systems. Synthesis of oligosaccharides requires the protection from hydroxyl groups present in the corresponding monosaccharide units. The existing methods of protection have drawbacks, including formation of anomeric mixtures, change in hydrophilicity or lipophilicity and solubility of the products, participation of the protecting groups in the reactions of the core of monosaccharide units, problems associated with chemoselectivity, regioselectivity and overall stereochemical outcomes of reactions. Additionally, there has been a spectral overlap of these protecting groups with carbohydrate core, which yielded more complex spectra. Therefore, the identification and synthesis of suitable alternative protecting groups have received attention in the oligosaccharide synthesis. The objective of the present study was to synthesize various fluorinated benzyl ethers of methyl-α-D-mannopyronoside and to evaluate these ethers as the alternative protecting groups for enhancing NMR resolution in the oligosaccharide synthesis. Various fluorinated benzyl ethers of methyl-α-D-mannopyronoside were prepared through the reaction of methyl-α-D-mannopyronoside with various fluorinated benzyl bromides by using Williamson ether synthesis method. Spectral analysis of these fluorinated benzyl ethers showed that the peaks of methylene carbons shifted to a value of 10-20 parts per million (ppm) to a high field region in the 13C NMR, compared to the non-fluorinated benzyl ether. As a result, the spectral complexity decreased and enhanced the spectral resolution. In this study, we concluded that fluorinated benzyl ethers could be a suitable alternative to the non-fluorinated benzyl ethers to protect the hydroxyl groups of monosaccharides in the synthesis of oligosaccharides.

Photo-Degradation of Orange G as an Environmental Pollutant with TiO2-ZnO Composite Material

The increasing water pollution is a great concern as millions of people don't have access to pure water in Bangladesh. A considerable number of people are dying of contaminated water each year not only in Bangladesh but all over the world. Many industries, tanneries, companies, etc. are emitting lots of environmentally hazardous materials into the surrounding water. Many of these pollutants are industrial dyes. The dyes loss from the industrial water during dyeing operation damage the esthetic merit of surface water. They minimize light penetration, hamper aquatic lives and hinder photosynthesis. Some dyes may also have toxic, mutagenic, and carcinogenic characteristics. The purpose of this research is to get rid of the pollutant dye Orange G before the water is contaminated. A method named photo-degradation using different light sources is used to mineralize Orange G dye with composite materials including TiO2-ZnO. This composite was prepared by the hydrothermal method. The photocatalytic behavior of the prepared composite TiO2-ZnO helps in minimizing the effect of this dye to save the water from contamination. The composite compoundwas studied by experimenting on photo-degradation with Orange G under different light sources such as visible light, UV light, and sunlight. The photo-degradation percentage was found to maximum of 79.60 in the presence of sunlight. The percentages of photo-degradation under UV light and visible light were 48.0 and 18.40 respectively.

Effect of Biomass-Based Catalyst in Walnut Shell/Polypropylene to BTX

Four biomass-based catalyst carriers with different pore structures were prepared by using a carbonization-activation method, followed by employment in the copyrolysis of Walnut Shell/Polypropylene (WNS/PP) to produce Benzene, Toluene and Xylene (BTX). Ten cycles were performed in each copyrolysis test in a bench-scaled tube furnace to determine the suitable pore size of the catalyst and excellent cycling performance for BTX production. In addition, Zn, Ni, and Ce were loaded with the selected catalyst carriers to synthesize the most suitable biomass-based catalyst. Results showed that the pore size and active center of the catalyst were the key factors affecting the WNS/PP catalytic copyrolysis. Biomass-based carrier with a pore size in the range of 0.55-1.2 nm was the most suitable to produce BTX in the optimal 10 cycle performance; it realized a relative BTX content of 9-20 area%, and a BTX mass yield of 23-67 mg/(graw) in the liquid-phase products from the WNS/PP copyrolysis. A catalyst loaded with 10 wt% Zn possessed the best catalytic effect with a relative BTX content of 39.49 area%, and a BTX yield of 111.13 mg/(graw)

Yamuna Action Plan-III: Impact on Water Quality of River Yamuna, India

Water is indispensable to sustain life and livelihood, and rivers serve as major reservoirs of water in manyparts of the world. River Yamuna is the major tributary of the River Ganges in India and is considered to be among the most polluted rivers of the world. The Yamuna Action Plan (YAP) is one of the largest river restoration projects in India and is initiated to clean the river. YAP is a bilateral arrangement between the governments of India and Japan, and consists of three Actions Plans-I, II and III. YAP-III is currently under execution with some of the major projects being the construction of the new Wastewater Treatment Plant (WWTP) at Okhla, rehabilitation and upgrading of WWTPs at Kondli and Rithala in the Delhi region. The impact of YAP-III with regard to these major projects on the reduction of the pollutant load reaching the river and cost-benefit has been evaluated in the current study. Findings from the study indicated that major projects such as construction of a new WWTP at Okhla (124 MGD) can effectively reduce the pollutant load by 283 kg/MGD of wastewater at a cost of Rs. 1161 crores while the rehabilitation project at Rithala (Phase I) can reduce the pollutant load by 92.5 kg/MGD wastewater at a cost of Rs. 300 crores. The present study indicates the need to evaluate projects in terms of cost-benefit analysis in addition to the economic and environmental evaluation for effective action. A holistic approach towards treatment of pollutant load in the river and prevention of further pollutants from reaching the river is required in addition to community awareness and participation for sustainable river water management.

Production of Plastic Cement Concrete from PVC Waste

The disposal of plastic wastes into the environment is a serious concern due to its limited biodegradability and production in excess quantity. The accumulation of enormous volumes of plastic waste is considered to be a major pollution problem and it is essential to find an alternate method to address such issues in an environmental-friendly and cost-effective way. The current research focused on the production of plastic cement concrete from waste polyvinyl chloride (PVC) generated from a polymer processing industry in varying proportions, and to modify the concrete properties. Polyvinyl chloride was partially replaced with Ordinary Portland Cement (OPC) by varying its compositions from 15% to 35% by weight (i.e. 15%, 20%, 25%, 30% and 35% OPC). The curing period was kept for 7 days after casting process. The produced plastic cement concrete was tested for compressive strength through Universal Testing Machine (UTM). Density and water absorption tests were also carried out on hardened concrete to assess the application of plastic cement concrete as a building material. The other characterization techniques employed are Fourier Transform Infrared Spectroscopy (FTIR) and X-Ray Diffraction (XRD) analyses. It was observed that up to 15% by weight of polyvinyl chloride could be replaced with OPC which exhibited higher compressive strength (19.25 MPa) compared to other mix proportions. A maximum density of 2.051 g/cm3 was obtained at a concrete mix composition corresponding to 25% replacement. The maximum water absorption percentage (5.86%) was observed at 35% plastic waste replacement. The studies demonstrate that the waste plastic material is considered to be a cost-effective, viable and sustainable way of reducing the environmental pollution.

Measurement of Complex Formation Process of Nickel (II) with Freshwater Fulvic Acids Using the Solubility Method

The complex formation process between Ni(II) and fulvic acids has been studied through the solubility method at pH = 9.0. The old suspension of Ni(OH)2 is used as a solid phase. Fulvic acids are isolated from Paravani lake by the adsorption-chromatographic method. The activated charcoal is used as a sorbent. The concentration of fulvic acids in model solutions changes from 1.1 × 10-5 mol/L to 4.4 × 10-5 mol/L. The value of molar mass of fulvic acids at pH = 9.0 was taken into consideration for the calculation of molar concentrations of fulvic acids. Before adding the ligand the initial concentration of nickel was 3.8 × 10-6 mol/L. This article has shown that, during complex formation process every 0.25 part of an associate of fulvic acids (Mw = 7610), inculcates into nickel's inner coordination sphere as an integral ligand, so it may be assumed, that the average molecular weight of the associate of fulvic acids which takes part in complex formation process equals to 1903. This part of the associate of fulvic acids was conventionally called the "active associate". The average molecular weight of the "active associate" was used for determining the concentration of free ligand and average stability constant (1:1), which equals to β = 1.07 × 107 (lgβ = 7.03).

Recent Trends in the Development of Benzimidazole Hybrid Derivatives and Their Antimalarial Activities

A parasite of the Plasmodium species initiates malaria. The parasite is transmitted to communities through the bite of an infected mosquito. Malarial resistance towards the commonly used antimalarial agents is a genuine human health problem. Benzimidazole derivatives exhibit a wide range of antimalarial activities against Plasmodium falciparum (P. falciparum) strain. The present review has summarized the antimalarial activity of benzimidazole hybrid derivatives and described its structural activity relationship (SAR) and quantitative structural-activity relationship (QSAR) model. A total of 14 papers were systematically reviewed. The literature survey has revealed that novel benzimidazole hybrid derivatives diminished the P. falciparum activity in the liver and gametocyte stages and inhibited heme synthesis and β-hematin formation. The QSAR models explain imminent antimalarial agent's growth through multiple linear regression (MLR) and artificial neural networks (ANN).

Synthesis and Characterization of Biosilica from Rice Husks as a Catalyst for the Production of Biodiesel

The synthesis of silica particles from rice husk is a research based on natural materials and is classified as green material. Preparation of biosilica catalyst from calcined rice husk ash was carried out by the hydrothermal method using rice husk ash mixed with NaOH solution at a ratio of 1:5 (w/v) with the reaction temperature of 110-120°C, the pressure of 0.15-0.2 MPa for 15-30 minutes. Biosilica results are then continued with the calcination process at a temperature of 200-500°C for one hour. Biosilica with calcination is then compared to biosilica without calcination. These two kinds of biosilica are then characterized to determine their performance. The biosilica characteristic test that was carried out included X-Ray Fluorescence (XRF), Scanning Electron Microscopy(SEM), and Brunauer-Emmett-Teller (BET). The XRF test results show that biosilica with calcination process has higher silica and silica oxide content than that without calcination. The surface morphology of biosilica with calcination and without calcination gives an uneven surface and consists of lumps and with uneven distribution on the surface of the biosilica sample. Biosilica with calcination process has a larger surface area, pore volume, and radius than biosilica without calcination process.