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Chitosan is formed by deacetylation of chitin using strong alkali at high temperatures. The content of the active amine groups in chitosan is widely used as an alternative natural coagulant that is environmentally friendly. So, it can be included in learning materials about the concept of sustainability. This study aimed to produce concept maps and Teaching Learning Sequences (TLS) based on scientists' conceptions of sustainability on the topic of water treatment using natural coagulants. The method used in this research was qualitative content analysis. The research instruments included content analysis formats and sustainability aspects. The content analysis process included literature collection, descriptive analysis, category selection, and material evaluation with didactic aspects. This research produced concept maps and TLS that described the relationship between water treatment using natural coagulants and colloid content. Additionally, TLS related to sustainability education in the form of learning about water treatment using natural coagulants from chitosan was also developed. The concept map and TLS that have been compiled show the relationship between mapping aspects of scientific literacy and environmentally friendly water treatment using natural coagulants. The research results can be used as a basis for developing teaching materials and didactic designs. [ABSTRACT FROM AUTHOR]

A detailed investigation of the hydrothermal crystallization of SAPO-34 in the presence of the novel 1-propylpyridinium hydroxide ([PrPy]OH) organic structural directing agent is presented. The synthesis conditions are systematically tuned to investigate the effects of various parameters (viz. concentrations of each reactant, crystallization time, and temperature) on the nucleation and crystallization of SAPO-34. The results show that a careful variation in each of the synthesis parameters results in the formation of competing phases such as SAPO-5, SAPO-35, and SAPO-36. Pure and fully crystalline SAPO-34 can be crystallized using a precursor hydrogel of a molar ratio of 2.0 Al: 4.7 P: 0.9 Si: 6.7 [PrPy]OH: 148 H2O at 200 °C for only 19 h, which is a shorter time than that found in previous studies. The prepared SAPO-34 is also very active in the esterification of levulinic acid and 1-propanol. By using microwave heating, 91.5% conversion with 100% selectivity toward propyl levulinate is achieved within 20 min at 190 °C. Hence, the present study may open a new insight into the optimum synthesis study of other zeolites using novel pyridinium organic moieties and the opportunity of replacing conventional harmful and non-recyclable homogeneous catalysts in levulinate biofuel synthesis. [ABSTRACT FROM AUTHOR]

This paper aims to elaborate on the results of the experimental assessment of the stability of TiO2-Polyester (POE) nanolubricant. There are six samples in this investigation, with each concentration of 0.02 vol%. The TiO2 nanoparticles were dispersed into synthetic lubricant POE for 30 min using a magnetic stirrer. Then, the samples were sonicated for 0, 40, 60, 80, 100, and 120 min, respectively--the visual observation for 720 hours, UV visible spectrophotometry, and absolute zeta potential employed to investigate the samples. After data acquisition, optimization with one factor at a time (OFAT) is applied to determine the most optimum sample. The results show that the sample with sonication treatment for 120 min is the most optimum. This finding was confirmed by the absorbance ratio value of 0.95 with an -80.48mV zeta potential. The output of ANOVA analysis shows the regression coefficient is 0.9999, and the adjusted R² value is 0.9998 with a p-value that is much smaller than 0.05, which is <0.0001. These results demonstrate that sonication duration has a significant effect on increasing the stability of TiO2-POE nanolubricant. [ABSTRACT FROM AUTHOR]

A hydrogel based on poly(vinyl alcohol) (V), Premna Oblongifolia Merr. extract (O), glutaraldehyde (G), and carbon nanotubes (C) has been synthesized in search of candidates to develop controlled‐release fertilizers (CRF). Referring to previous studies, O and C can be considered as two materials that have potential as modifiers in synthesizing CRF. This work is comprised of hydrogel synthesis, their characterisation, including measuring swelling ratio (SR) and water retention (WR) of VOGm, VOGe, VOGmC3, VOGmC5, VOGmC7, VOGmC7‐KCl, and release behaviour of KCl from VOGmC7‐KCl. We found that C interacts physically with VOG, increased the surface roughness of VOGm, and reduced the VOGm crystallite size. The addition of KCl into VOGmC7 reduced the pore size and increased the structural density of VOGmC7. The thickness and the C content of VOG affected its SR and WR. The addition of KCl into VOGmC7 reduced its SR, but did not significantly affect its WR. [ABSTRACT FROM AUTHOR]

Biopolymer are expected to be environmentally compatible and to have great potential application as membranes material. The chitosan-poly (ethylene glycol)/PEG based composite membranes was successfully synthesized via inversed phase method. The effect of multiwalled carbon nanotubes (MWCNT) as nanofiller on properties and performances of composite membranes were intensively evaluated. The membrane was prepared by mixing of chitosan and PEG solutions at the same composition ratio while MWCNT amount in the mixture was varied. The synthesized membrane was characterized by means of FTIR spectroscopy, scanning electron microscopy (SEM), contact angle, and tensile strength measurement. The performance of composite membrane on filtration was evaluated in term of flux (permeability) and rejection (rejection) tests. The results showed that the optimum volume ratio of composite membrane solution was found at 30:10:7.5 for chitosan/ PEG/ MWCNT, respectively, as indicated by the largest flux. Insertion of MWCNT nanofiller notably enhanced hydrophilicity, porosity, and mechanical properties of composites membranes that are confirmed by contact angle, SEM images and elongation forces value, respectively. The MWCNT nanofiller remarkably increased both of flux and rejection of composite membranes up to 60 Lm2h-1 and 96%, respectively. The remarkable enhancement of composite membrane performance is attributed to the effective interaction of MWCNT with polymeric matrix.

The vibrations and noise of the internal combustion engine may be affected by several factors such as combustion pressure, movement of the piston-crank mechanism, coolant factor flow, engine body, and fuel inlet of the injector. Various ways have been done to reduce vibration and noise in the engine, including fuel. Alternative biofuels can be used in internal combustion engines without having to modify and change parameters on the machine. Several researchers have studied the effects of vibration and noise in the engine using various fuel mixtures. The results from some literature reported that biodiesel blend fuels proved to reduce vibration and noise in engines as compared to pure diesel. Meanwhile, ethanol fuel mixed with gasoline shows significant vibration changes at engine speeds of 1,500 and 2,500 rpm. The review aims to analyse the effects of vibration and noise on engines fueled by fuel mixtures, as well as fuel properties used as a move for future research. Based on the analysis from several kinds of literature, it shows that the use of biodiesel fuel and ethanol-gasoline can reduce vibration and noise.

Biodiesel is an alternative fuel that is used in a diesel engine as a substitute for diesel fuel. However, using biodiesel without a modified engine can cause higher NOx emissions. Therefore, to reduce harmful emissions some strategy must be proposed or or a change in the injection is performed. In this study, injection schemes and engine performance injection time, emissions and firing characteristics of biodiesel mixing results in engines were investigated by using GT-POWER simulation. The simulations in this study were conducted on diesel engines to observe the accuracy in experimental results . The engines were tested at speeds of 1100 rpm, 1300 rpm, and 1500 rpm by using a biodiesel-diesel fuel mixture. The simulation results showed that NOx emissions were found to drop below 100 ppm when biodiesel fuel was used for all performed operations. Meanwhile CO emissions were also decreased by 10%-15% when biodiesel fuel was used, and the thermal efficiency level increased by 2% and 3.5% as compared to pure diesel. The ratio of NOx reduction rates of biodiesel and diesel was 11%-14% as compared to 9.5% with pure diesel. Based on the simulation result, it was shown that the accuracy level of simulation data with experiment was 97%. So this result can be the future testing standard and simulation by using GT-POWER could also be used especially for the automotive industry.

A highly selective electrochemical sensor based on a molecularly imprinted polymer (MIP) to be developed for uric acid detection in the presence of dopamine as an interference molecule was demonstrated in this study. This non-enzymatic uric acid sensor was developed by electropolymerizing poly-pyrrole onto a composite of electrochemically reduced graphene oxide (ErGO) and poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) on a glassy carbon electrode (GCE) to give MIP/ErGO/PEDOT:PSS electrodes. The structural properties, surface morphology, and electrochemical interface of this fabricated uric acid sensor was then characterized using infrared spectroscopy, scanning electron microscopy, atomic force microscopy, and electrochemical impedance spectroscopy. This fabricated non-enzymatic electrochemical sensor (MIP/ErGO/PEDOT:PSS modified GCE) also showed excellent analytical performance at the optimum ratio of monomer/template concentration and optimized electropolymerization conditions, for example in the low concentration range of 0.1–100 μM with a detection limit of 0.05 μM towards uric acid detection in the presence of dopamine. Furthermore, this fabricated uric acid sensor also exhibited good reproducibility and stability for uric acid measurements in the presence of dopamine for 5 consecutive days. In addition, this sensor demonstrates highly selective detection of uric acid in the presence of several interfering species such as dopamine, urea, glucose, magnesium ions, and ascorbic acid. This fabricated uric acid sensor ultimately showed satisfactory uric acid measurement in samples of human urine and is expected to be used in early-stage disease diagnosis. [ABSTRACT FROM AUTHOR]

Biodiesel fuel can be used as an alternative to mineral diesel, its blend up to 20% used as a commercial fuel for the existing diesel engine in many countries. However, at high blending ratio, the fuel properties are worsening. The feasibility of pure biodiesel and blended fuel at high blending ratio using different chemical additives has been reviewed in this study. The results obtained by different researchers were analysed to evaluate the fuel properties trend and engine performance and emissions with different chemical additives. It found that, variety of chemical additives can be utilised with biodiesel fuel to improve the fuel properties. Furthermore, the chemical additives usage in biodiesel is inseparable both for improving the cold flow properties and for better engine performance and emission control. Therefore, research is needed to develop biodiesel specific additives that can be adopted to improve the fuel properties and achieve best engine performance at lower exhaust emission effects.

A study on the application of oxygenated turpentine oil as a bio-additive in diesel fuel was conducted. The purpose of this research was to investigate the effect of oxygenated turpentine oil additive in diesel fuel on the performance and emission characteristics in diesel engines. Oxygenated turpentine oil is obtained from the oxidation process of turpentine oil. In this experimental study, the influences of oxygenated turpentine oil-diesel blended fuel OT0.2 (0.2% vol oxygenated turpentine oil and 99.8% vol diesel) were compared with pure diesel on engine performance, and emission characteristics were examined in a one-cylinder four-stroke CI engine. The test was performed at two engine loads (25% and 50%) and seven engine speeds (from 1200-2400 rpm with intervals of 200 rpm). The physiochemical characteristics of test fuels were acquired. The engine indicated power, indicated torque, fuel flow rate, and emissions (carbon dioxide, CO2; carbon monoxide, CO; and nitrogen oxide, NOX) were examined. The results revealed that the engine power shows slight increments of 0.7-1.1%, whereas the engine torque slightly decreased with oxygenated turpentine usage compared to pure diesel in most conditions. Furthermore, a reduction in NOX emission decreased by about 0.3-66% with the addition of oxygenated turpentine in diesel compared to diesel. However, usage of OT0.2 decreased fuel flow rate in most speeds at low load but gave a similar value to diesel at 50% load. CO emissions slightly increased with an average of 1.2% compared to diesel while CO2 emissions increased up to 37.5% than diesel. The high-water content, low cetane number, and low heating value of oxygenated turpentine oil were the reasons for the inverse effect found in the engine performances. [ABSTRACT FROM AUTHOR]

The present study is aimed at investigating the subchronic toxicity of ethanol extract of Mucuna pruriens seeds from Indonesia. A total of 120 rats Wistar strain, both sexes, were used in this study. Both were divided into one control group, three treated groups, and two satellite groups. The extract in different doses was administered orally for 90 days for the treated groups, while 120 days for the satellite groups. The subchronic toxicity was evaluated using various parameters including death, motoric activity, body weight, haematology parameters, biochemical parameters, and organ weight along with the histopathological study. There was no mortality and no significant change in motoric activity, body weight, several haematological parameters, and glucose levels. Significant differences were found in levels of cholesterol, triglyceride, AST and ALT, BUN, and creatinine. Degeneration of some tissues was seen in the kidneys and the liver. The ethanol extract of Mucuna pruriens seeds from Indonesia has a reversible subchronic toxicity to the liver and kidneys. [ABSTRACT FROM AUTHOR]

Carbon aerogels contain both mesopores and micropores. In this study, benzene/CCl4 was adsorbed in the pores of carbon aerogels (both mesopores and micropores) and their phase behaviours were examined using differential scanning calorimetry. The bulk solid benzene melted at 278 K and the melting temperatures of benzene confined inside the mesopores and micropores of carbon aerogels were 258 and 293 K, respectively. Although the melting temperature depression of condensates in mesopores is well known, the observed elevation of the melting temperature for micropores is very limited in the strongly interacted system. Similar melting behaviours were observed for the confined CCl4; depression by 45 K in mesopores and elevation by 48 K in micropores showed about two times the change as compared with that of confined benzene. [ABSTRACT FROM AUTHOR]

Abstract: Tailoring electronic properties of single wall carbon nanohorn (SWCNH) is expected to develop the application potential in various fields. SWCNH is efficiently modified with iodine molecules by liquid phase adsorption. The adsorption isotherm of iodine on SWCNH was Langmuirian with the saturated adsorption amount of 185±10mgg−1 (coverage 0.18), indicating a specific interaction between SWCNH and iodine. The DC electrical conductivity of SWCNH film prepared by dip-coating method increased with the iodine adsorption amount almost by a factor 10. [ABSTRACT FROM AUTHOR]

A detailed study on the synthesis of chitosan nanoparticles under ultrasonication is reported in this paper. By using this simple technique, chitosan particles in nanometer range can be easily prepared without using any harmful and expensive chemicals. The results show that increasing the ultrasonic irradiation time and ultrasonic wave amplitude are the key factors for producing discrete chitosan nanoparticles with narrow particle size distribution. The resulting nanoparticles show superior turbidity removal efficiency (75.4%) and dealkalization (58.3%) in wastewater treatment than the bulk chitosan solid (35.4% and 11.1%, respectively), thus offering an eco-friendly and promising approach for treating wastewater via the coagulation/flocculation process. [ABSTRACT FROM AUTHOR]

Offretite zeolite synthesis in the presence of cetyltrimethylammonium bromide (CTABr) is reported. The offretite crystals were synthesized with a high crystallinity and hexagonal prismatic shape after only 72 h of hydrothermal treatment at 180 °C. The CTABr has dual-functions during the crystallization of offretite, viz. as structure-directing agent and as mesoporogen. The resulting offretite crystals, with a Si/Al ratio of 4.1, possess more acid sites than the conventional offretite due to their high crystallinity and hierarchical structure. The synthesized offretite is also more reactive than its conventional counterpart in the acylation of 2-methylfuran for biofuel production under non-microwave instant heating condition, giving 83.5% conversion with 100% selectivity to the desired product 2-acetyl-5-methylfuran. Hence, this amphiphile synthesis approach offers another cost-effective and alternative route for crystallizing zeolite materials that require expensive organic templates. [ABSTRACT FROM AUTHOR]

The formation of SAPO-5 molecular sieves is studied under hydrothermal conditions in the presence of a new templating agent, 1-benzyl-2,3-dimethylimidazolium hydroxide ([bzmIm]OH). The syntheses were carried out by varying the synthesis parameters, viz. crystallization temperature, heating time and reactants molar composition (SiO2, Al2O3, P2O5, [bzmIm]+, H2O) in order to investigate the role of each synthesis parameter on the formation of SAPO-5. The results showed that these synthesis parameters had significant influences on the entire crystallization process (induction, nucleation, crystal growth, and Ostwald ripening) and physicochemical properties of SAPO-5 (morphology and crystal size). Moreover, this study also demonstrated a fast hydrothermal synthesis approach where a SAPO-5 molecular sieve with hexagonal prism morphology could be crystallized within 10 h instead of days using a novel [bzmIm]OH heterocyclic template, thus offering an alternative route for synthesizing zeolite-like materials for advanced applications. [ABSTRACT FROM AUTHOR]

MER-type zeolite is an interesting microporous material that has been widely used in catalysis and separation. By carefully controlling the synthesis parameters, a procedure to synthesize K-MER zeolite crystals with various morphologies has been developed. The silica, water and mineralizer content in the synthesis gel, as well as crystallization time and temperature, have a profound impact on the crystallization kinetics, resulting in zeolite solids with various degrees of crystallinity, crystal sizes and shapes. K-MER zeolite crystals with nanorod, bullet-like, prismatic and wheatsheaf-like morphologies have been successfully obtained. The catalytic performances of the K-MER zeolites in cyanoethylation of methanol, under novel non-microwave instant heating, have been investigated. The zeolite in nanosize form shows the best catalytic performance (94.1% conversion, 100% selectivity) while the bullet-like zeolite gives poorest catalytic performance (44.2% conversion, 100% selectivity). [ABSTRACT FROM AUTHOR]

Cs–pollucite can be a potential solid base catalyst due to the presence of (Si-O-Al)−Cs+ basic sites. However, it severely suffers from molecular diffusion and pore accessibility problems due to its small micropore opening. Herein, we report the use of new organosilane, viz. dimethyloctadecyl[3-(trimethoxysilyl)propyl]ammonium chloride (TPOAC), as a promising pore-expanding agent to develop the hierarchical structure in nanosized Cs–pollucite. In respect to this, four different amounts of TPOAC were added during the synthesis of hierarchical Cs–pollucite (CP-x, x = 0, 0.3, 1.0, or 2.0, where x is the molar ratio of TPOAC) in order to investigate the effects of TPOAC in the crystallization process of Cs–pollucite. The results show that an addition of TPOAC altered the physico-chemical and morphological properties of hierarchical Cs–pollucite, such as the crystallinity, crystallite size, pore size distribution, surface areas, pore volume, and surface basicity. The prepared solids were also tested in Claisen–Schmidt condensation of benzaldehyde and acetophenone, where 82.2% of the conversion and 100% selectivity to chalcone were achieved by the CP-2.0 catalyst using non-microwave instant heating (200 °C, 100 min). The hierarchical CP-2.0 nanocatalyst also showed better catalytic performance than other homogenous and heterogeneous catalysts and displayed a high catalyst reusability with no significant deterioration in the catalytic performance even after five consecutive reaction runs. [ABSTRACT FROM AUTHOR]