Search

Undoubtedly, industrial activities have produced a large amount of waste, which has significantly contributed to the global environmental problem. The palm oil sector, which is considered a water-intensive industry, is one of the industrial sectors that have become a major source of severe water pollution concerns. Normally, 50% of the freshwater used during the extraction of crude palm oil will end up in the production of undesirable liquid waste. Thus, proper regulation and enforcement are required to control the discharge of such waste to ensure the sustainability of water resource management. Based on research databases such as Scopus, ScienceDirect, Web of Science and PubMed the total number of publications focused on palm oil mill effluent (POME) treatment has increased significantly over the past five years. The increase in publications shows the growing concern about the POME issue among the scientific community. This mini review focuses on selected biological treatment techniques for remediation of POME focusing on ponding systems, bioadsorption, activated sludge, microorganism and plant, aerobic biodegradation and integrated/hybrid treatment strategies. The summary of optimum operating conditions, characteristics of the treatment system, properties of materials and performance of each treatment are discussed in detail. To achieve a high level of contaminant removal performance, it is critical to discover the synergistic effect between the treatment procedures, materials employed, operational cost, and circumstances.

Water pollution has become one of the most serious environmental issues recently, especially in relation to chemical-containing wastewater. Uncontrolled industrial waste, including large amounts of dye-containing wastewater from textile industries, needs intensive attention. In this work, the synthesis of Fe3O4@SiO2 nanocomposite biogenic silica from Salacca zalacca leaf ash was conducted for the photo-Fenton-like degradation of dye waste. The use of Salacca zalacca leaf ash and the nanoflake form is the novelty of this work. The physicochemical characterization of the material was conducted using X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), and diffuse reflectance UV-visible spectroscopy (UV-DRS) analyses, and photocatalytic activity of material was investigated in wet peroxidation of rhodamine B and batik wastewater. The results showed homogeneously dispersed Fe3O4 in SiO2 support with a nanoflake form, and a crystallite size of 44.9 nm was obtained. XRD investigation revealed the single phase of Fe3O4, which is consistent with the TEM analysis. The bandgap energy of 2.21 eV was reported from UV-DRS measurements, which influenced the increasing photocatalytic activity and reusability of the nanocomposite compared to pure Fe3O4. The photocatalyst showed the maximum degradation efficiency (DE) of 99.9% after 60 min, and the reusability feature was expressed, as there was an insignificant change in the DE over the fifth cycle of use. The material exhibited photocatalytic oxidation of batik wastewater as the removal of total suspended solids, chemical oxygen demand, and color reached 95.55%, 89.59%, and 90.00%, respectively.

Nitrogen stress condition is believed to increase the production of lipid in microalgae, but the synthesis of both lipid and carbohydrate is less known. Therefore, the effect of nitrogen stress condition on the synthesis of lipid and carbohydrate of Tetradesmus obliquus UPSI-JRM02 was studied in a 2 L bioreactor system. The highest lipid and carbohydrate yields achieved under nitrogen stress condition were 37% and 23%, respectively. Nitrogen stress condition induced the accumulation of carbohydrate at early stage but started to reduce on day 4 when the carbon shifted towards lipid production. The fatty acid profile produced under nitrogen stress condition was composed of 54% polyunsaturated fatty acid (PUFA), 43% saturated fatty acid (SFA) and 3% monounsaturated fatty acid (MUFA). The biofuel properties of T. obliquus obtained under the nitrogen stress condition was within the range of biodiesel standard and is most suitable for the usage in cold country.

In recent years, the development of nanoparticle materials for water treatment has received great attention. From an industrial technological view point, the application of nanomaterials in the twenty-first century for water treatment will be the focal point of advanced materials design, processing and progress. In this context, the potential utilisation of different types of flocculants to clean up contaminated water becomes important to address the tremendous increase of water pollution resulting from continued high-level global industrialisation. A number of researchers have investigated the effectiveness of various nanoflocculants for this purpose. Although these nanoflocculants have been reported to successfully treat contaminated water, their flocculation performances are different. To the best of our knowledge, there is no review article which summarises the application and performance of nanoflocculants in the treatment of water containing various types of contaminants. This review summarises the recent development of a wide range of nanoflocculants for the treatment of water polluted particularly by heavy metals, dyes and bacteria. The influence of physicochemical properties of nanoflocculants upon their performance and optimum flocculation conditions is discussed in detail. This review will provide a useful source of information for researchers working on the advancement of cost-effective and environmentally friendly nanoflocculants.

The proliferation of mosquito-borne diseases is a major health concern worldwide. An effective strategy to prevent the transmission of mosquito-borne diseases is using larvae control. Cinnamaldehyde, a substance from the cinnamon tree, is widely used in larvicide formulations, yet applications are limited due to the poor water solubility of cinnamaldehyde. Therefore, we prepared a sodium alginate–chitosan nanocomposite as a nanocarrier of cinnamaldehyde, and we tested the effect of this encapsulated cinnamaldehyde on Aedes aegypti larvae. The nanocomposites/cinnamaldehyde formulations were characterised by Fourier transform infrared spectroscopy and nuclear magnetic resonance, which evidenced encapsulation. A ratio of 150:1 w/w nanocomposite/cinnamaldehyde induced the highest encapsulation efficiency of 95.25%, a loading capacity of 81.42%. This extended the cinnamaldehyde release by 28 h and controlled mosquito larvae.

It is known that palm oil is one of the top selling raw materials that are widely used in both food and non-food industries. It is also widely used as a feedstock for biofuel production. However, the palm oil industry produces a huge amount of effluent that normally contains undesirable contaminants and suspended solids (SS), with high chemical oxygen demand (COD) and biochemical oxygen demand (BOD) values. Hence, it is imperative to ensure the sustainable management of palm oil production and to prevent serious environmental pollution. Various techniques are available to treat palm oil mill effluent (POME). This review summarizes the compilation of articles published in the period of 2010 to 2020 that focused on the development of treatment techniques for POME. Academic databases including Scopus, ScienceDirect, Web of Science, and PubMed were used to search for related articles. This review discusses the performance and highlights the optimum operating conditions for each chemical treatment technique. This review is not only relevant to researchers who work on the advancement and innovation of remediation technologies for POME, but it is also significant for researchers who deal closely with environmental pollution, water resource management, environmental protection, and flora and fauna conservation.

Nowadays, concern regarding health epidemics has led to extensive development of functional textiles that have protective functions. Clothing and fabric with insect repellent finishes is a promising and effective way to protect body from insect bites that may carry pathogens. In recent years, several innovations in insect repellent textiles, in particular on new materials and techniques to improve the efficacy and durability of the fabric, have been developed. This review discusses issues and challenges associated with insect repellent finishes. This review also focuses on materials used as improvers in insect repellent textiles whether at the production stage (used in modification fiber or yarn) or in the formulation for post-treatment. The techniques of synthesis, the rates of release, the durability, and insect repellency have also been highlighted in this review. This review offers valuable input to scientists who work in the field of functional textiles and especially from countries with insect-borne disease problems.

Photocatalyst of hydroxyapatite–nano TiO2 (HAp-nTiO2) was prepared from phosphatation of calcined cockle (Anadara granosa) shells followed by dispersion of nano TiO2 powder into HAp precipitate and calcination at 400 °C for 2 h. The prepared material was characterized using X-ray diffraction, scanning electron microscope–energy dispersive X-ray spectrophotometry, gas sorption analysis, and UV-Vis diffuse reflectance spectrophotometry. The photocatalytic activity of the material was evaluated for methyl violet degradation over photocatalysis and photooxidation mechanism. The results showed that the homogeneous dispersion of TiO2 in the HAp-nTiO2 composite was achieved, as seen in the X-ray diffraction analysis, diffuse reflectance UV-Vis, and gas sorption analyses. The physicochemical and photocatalytic character of the composite exhibited the positive role of HAp as TiO2 support in enhancing the photocatalytic activity with a higher turnover number and reusability property than that of pure TiO2. It was also noted that the HAp-nTiO2 composite demonstrated rapid methyl violet degradation over photooxidation rather than by photocatalytic mechanism.

Andrographis paniculata Ness is one of the plants that is under explored and could contain potentially active substances to serve as an antimalarial. Structure investigation of major compounds that have responsibility for the antimalarial activity of Andrographis paniculata Ness’s n-hexane extract is very important so that it is known whether the antimalarial activity is synergistic or from the major compounds. Menthol and dioctyladipate as major component from n-hexane extract of Andrographis paniculata Ness have been succesfully isolated using simple and inexpensive methods. The solvent system used are n-hexane : ethyl acetate (10:1) and n-hexane: chloroform (10:3) consecutively either for column or preparative thin layer chromatography. FT-IR, 1H-NMR and GC-MS were used to determine the structure of compounds. The activity of n-hexane extract, menthol and dioctyladipate related to the inhibition of heme polymerization have been done comprehensively. The inhibition of heme polymerization activity of isolate compounds and n-hexane extract are classified to a good level (dioctyl adipate IC50 = 1.15 ± 0.41 mg/mL, menthol IC50 = 0.31 ± 0,01 mg/mL, and n-hexane extract IC50 = 0.07 ± 0.03 mg/mL) and potentially as antimalarial. From the IC50, the antimalarial activity of Andrographis paniculata Ness’s n-hexane extract is working synergistically, not by the major compounds.

This study investigates the potential of N-octyl chitosan derivatives, namely N-octyl-O-sulfate chitosan (NOOSC), N-octyl-N-succinyl chitosan (NONSC) and N-octyl-O-glycol chitosan (NOOGC) as amphiphilic carrier agents for atrazine in water-insoluble herbicide formulations. The N-octyl chitosan derivatives were characterised using several analytical instruments such as Fourier Transform Infrared (FTIR) Spectrometer, CHNS-O Elemental Analyser (CHNS-O), Transmission Electron Microscope (TEM), Thermogravimetric Analyser (TGA), Differential Scanning Calorimeter (DSC) and Fluorescence Spectrometer. The encapsulation of atrazine by N-octyl chitosan derivatives was studied using a High Performance Liquid Chromatography (HPLC). The FTIR spectra of N-octyl chitosan derivatives confirmed the presence of hydrophobic and hydrophilic groups on chitosan backbone. TEM images revealed that N-octyl chitosan derivatives have formed self-aggregates with a spherical shape. The CMC values for N-octyl chitosan derivatives were between 0.06 and 0.09 mg/mL. The encapsulation efficiency (EE) values for amphiphilic chitosan were greater than 90%. The release profiles showed different release behaviour of pure herbicide in solution as compared to atrazine-loaded N-octyl chitosan derivatives. Results suggest that the chitosan derivatives offer promising characteristics that enable them to act as effective carrier agents for atrazine. In conclusion, the application of N-octyl chitosan derivatives could reduce the use of organic solvents in herbicide formulations by 37.5%.

In the present study, gelatin–carboxymethyl cellulose blend film was synthesized, characterized and applied for the first time to preserve cherry tomatoes (Solanum lycopersicum var. cerasiforme) and grapes (Vitis vinifera). Gelatin (Gel) film forming solution was incorporated with carboxymethyl cellulose (CMC) at three volume per volume (Gel:CMC) ratios, namely 75:25, 50:50 and 25:75. CMC treatment has improved the transparency, tensile strength (TS), elongation at break (EAB), water vapor permeability and oxygen permeability of gelatin films. A pronounced effect was obtained for 25Gel:75CMC film. The TS and EAB values were increased from 25.98 MPa and 2.34% (100Gel:0CMC) to 37.54 MPa and 4.41% (25Gel:75CMC), respectively. A significant improvement in antimicrobial property of gelatin films against two food pathogens, namely Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) was obtained in the presence of CMC. The effectiveness of gelatin–CMC blend films to extend the shelf life of agricultural products was evaluated in a 14-day preservation study. The gelatin–CMC films were successfully controlled the weight loss and browning index of the fruits up to 50.41% and 31.34%, respectively. Overall, gelatin–CMC film is an environmental friendly film for food preservation. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1007/s13197-019-03809-3) contains supplementary material, which is available to authorized users.

Development of low-cost, sustainable and environmentally friendly biodiesel is a key focus in the energy industry worldwide. It is known that selecting suitable raw feedstock materials and optimising an efficient transesterification process are crucial in biodiesel production. Effective and realistic strategies are imperative in order to boost the quantity and quality of biodiesel production. In fact, scientists and researchers have put great effort to improve the market value of their biodiesel products. In recent years, the feasibilities of several raw materials as feedstocks to produce biodiesel have been assessed by researchers. These materials were reported able to produce biodiesel that met international standards, namely the American Society for Test and Materials D6751 and European Standard 14214. Although these biodiesel products have met the quality criteria, their fatty acid methyl ester (FAME) contents differ. This review focuses on optimum conditions (methanol/oil molar ratio, amount of catalyst, reaction temperature and reaction time) of transesterification process for biodiesel production from various feedstocks. The influence of these factors on FAME composition is also discussed. This review is beneficial to scientists working on biodiesel production particularly for the evolution of eco-friendly and low-cost biodiesel.

It is necessary to instill concern about the environment, particularly the management of solid waste among youngsters as habits are easily inculcated at a young age. This study assesses municipal solid waste (MSW) recycling behavior among students in Putrajaya, Malaysia. The data were analyzed using descriptive and inferential analyses. There is a moderate positive correlation between the Theory of Planned Behavior (TPB) and Other Determinant Factor (ODF) with students’ recycling behavior, r=.638. The findings indicate that attitude and subjective norms of the TPB influenced student recycling behavior. In addition, awareness, recycling practices, and situational factors of the ODF influenced students’ recycling behavior. In conclusion, formal education and outsource programs could educate students concerning environmental issues.

In this study, the synthesis of ZnO/SiO2 nanocomposites using bamboo leaf ash (BLA) and tested their photocatalytic activity for rhodamine B decolorization have been conducted. The nanocomposites were prepared by the sol–gel reaction of zinc acetate dihydrate, which was used as a zinc oxide precursor, with silica gel obtained from the caustic extraction of BLA. The effect of the Zn content (5, 10, and 20 wt%) on the physicochemical characteristics and photocatalytic activity of the nanocomposites was investigated. The results of X-ray diffraction, scanning electron microscopy, gas sorption, and transmission electron microscopy characterization confirmed the mesoporous structure of the composites containing nanoflower-like ZnO (wurtzite) nanoparticles of 10–30 nm in size dispersed on the silica support. Further, the nanocomposites were confirmed to be composed of ZnO/SiO2 by X-ray photoelectron spectroscopy analysis. Meanwhile, diffuse-reflectance UV–visible spectrophotometry analysis of the nanocomposites revealed band gap energies of 3.38–3.39 eV. Of the tested nanocomposites, that containing 10 wt% Zn exhibited the highest decolorization efficiency (99%) and fastest decolorization rate. In addition, the degradation efficiencies were not reduced significantly after five repeated runs, demonstrating the reusability of the nanocomposite catalysts. Therefore, the ZnO/SiO2 nanocomposite obtained from BLA is a promising reusable photocatalyst for the degradation of dye-polluted water.

Rotenone is a hydrophobic organic compound with the excellent insecticidal property. However, its hydrophobicity and the short period of efficacy due to rapid degradation in the presence of UV light and air have limited its application as an insecticide. This study studied the effects of hydrophobic alkyl groups on encapsulation and controlled release of rotenone by amphiphilic chitosan derivatives namely, octyl glycol chitosan (OGC) and lauryl glycol chitosan (LGC) were assessed. The physical and chemical properties of OGC and LGC were characterized using Fourier Transform Infrared (FTIR) Spectrometer, CHNO Elemental Analyzer, UV-Visible Spectrophotometer, Fluorescence Spectrofluorometer, and Differential Scanning Calorimetry (DSC). The efficiency of OGC and LGC to encapsulate for rotenone in its micelles was determined by using a High-Performance Liquid Chromatography (HPLC). FTIR and CHNO elemental analyses confirmed the amphiphilic chitosan derivatives were successfully synthesized using the reverse micelles method. The finding from the solubility study shows that the addition of the glycol group to the chitosan backbone has enhanced chitosan’s solubility properties in neutral and basic media. OGC and LGC exhibited good affinity towards rotenone with an encapsulation efficiency of more than 90%. The in vitro release study showed that the OGC and LGC could control the release of rotenone from its micelles. This study demonstrates that OGC and LGC showed beneficial properties to be further developed as a potential carrier in the pesticide formulation.

Microalgae are known as an alternative source of biomass energy to replace fossil fuels. The aim of the present study is to optimise the growth conditions and increase the lipid, carbohydrate and b...

In this study, the effectiveness of lala clam (Orbicularia orbiculata) shell, a fishery waste, as an adsorbent for removal of Cd(II), Cu(II) and Pb(II) ions from contaminated water was evaluated by characterization and adsorption studies. The characterization study was performed using Field Emission Scanning Electron Microscopy (FESEM), Energy Dispersive X-ray (EDX) Spectroscopy and Fourier Transform Infrared (FTIR) Spectroscopy techniques. The effects of solution pH (pH 1.0 to 6.0), adsorbent dosage (0.125 to 0.750 g) and initial adsorbate concentration (10 to 200 mg/L) on adsorption capacity of lala clam shell were studied. The capability of lala clam shell to remove metal ions from aqueous solution was assessed in both single- and mix-metal systems. The adsorption equilibrium data were fitted to Freundlich and Langmuir isotherm models. At an optimum solution pH of 6.0 and initial metal ion concentration of 200 mg/L, the maximum adsorption capacity (Qmax) values of Cd(II), Cu(II) and Pb(II) ions were determined as 66.66, 64.94 and 100.00 mg/g, respectively. The removal performance of lala clam shell (63.80 to 93.79%) for metal ions from battery manufacturing wastewater was comparable to that of three commercial activated carbons derived from olive tree wood (73.01 to 94.83%), coconut shell (68.10 to 95.17%) and bamboo (69.33 to 94.48%), which are commonly used for water treatment in Libya, Malaysia and Indonesia, respectively. The results obtained from this study suggest that lala clam shell exhibits a great potential to be used as an effective alternative to expensive adsorbents for water treatment.

Biodiesel from insect larvae is an alternative to plant biodiesel, which have issues of using edible plants. On the contrary, insects can grow on waste. Although the conversion of larval lipids to biodiesel is known, characterisation of larval biodiesel is rarely reported. Here, black soldier fly larvae were cultivated for 20 days on kitchen waste. Larval lipids were extracted and converted to biodiesel by two-step transesterification. Analysis by optical polarisation microscopy from − 5 to + 15 °C showed tiny needle-like shaped crystals. Fourier transform infrared spectra of black soldier fly biodiesel revealed absorption bands at 1459 and 1435 cm−1 corresponding to methyl ester, the main functional group of biodiesel. Nuclear magnetic resonance (NMR) analysis confirmed the presence of methyl ester by showing peaks at 3.6 and 2.3 ppm by 1H NMR, and at 176 and 51.56 ppm by 13C NMR. Overall, our results confirm the successful conversion of black soldier fly larval lipid to biodiesel. This biodiesel met the American Society for Test and Materials D6751 and European Standard 14214.

The environmental pollution that results from the excessive usage of pesticides has been threatening the communities for decades. In this study, carboxymethyl cellulose (CMC) is proposed as a coating agent to encapsulate zinc hydroxide nitrate–sodium dodecylsulphate–imidacloprid (ZHN–SDS–IC) for the implementation of controlled release formulation (CRF) in pesticide. The physicochemical properties of the ZHN–SDS–IC–CMC were characterised so that their crystallinity, thermal behaviour and surface morphology could be examined. The findings from the release study revealed the potential for CMC to prolong the release of imidacloprid (IC). A strong hygroscopic and adequate swelling characteristic enabled the CMC to develop an external gel layer on the surface of the ZHN–SDS–IC–CMC that acted as an additional barrier and slowed the release of the intercalated IC. The ZHN–SDS–IC–CMC that was synthesised can contribute to overcoming the environmental issues due to excessive usage of pesticides and can create a better future for the community.

Development of environmentally-friendly pesticides for sustainable agriculture is a key focus in the agrochemical industry. Identifying novel active ingredients and improving the delivery system of a pesticide are the main challenges in developing new pesticides. Strategies for the control of delivery systems for slow and sustained release of agrochemicals are of great interest to environmental scientists. In this context, the selection of materials to be used as carrier agents in pesticide formulations is crucial. In recent years, the efficacy of several materials for agrochemical formulations has been evaluated by researchers. These materials have unique properties, such as being biodegradable and biocompatible, and having low toxicity and involving a simple preparation process. This review summarises recent applications of various materials in pesticide formulations. The application of the materials can effectively encapsulate or bind the pesticide’s active ingredients in the material’s matrix with a sustained release profile and slow mobility in soil. This review also discusses some issues and concerns that are faced in formulating pesticide products.

In this study, an amphiphilic chitosan derivative namely N,N-dimethylhexadecyl carboxymethyl chitosan (DCMC) was synthesised and applied for the first time as a carrier agent for rotenone. The physical and chemical properties of DCMC were characterised by using Fourier Transform Infrared Spectrometer (FTIR), Proton Nuclear Magnetic Resonance Spectrometer ((1)H NMR), CHN-O Elemental Analyser, Thermogravimetric Analyser (TGA) and Differential Scanning Calorimeter (DSC). DCMC was soluble in acidic (except pH 4), neutral and basic media with percent of transmittance (%T) values ranged from 67.2 to 99.4%. The critical micelle concentration (CMC) was determined as 0.095mg/mL. Transmission Electron Microscopy (TEM) analysis confirmed that DCMC has formed self-aggregates and exhibited spherical shape with the size of 65.5-137.0nm. The encapsulation efficiency (EE) and loading capacity (LC) of DCMC micelles with different weight ratios (DCMC:rotenone; 5:1, 50:1 and 100:1) were determined by using High Performance Liquid Chromatography (HPLC). The weight ratio of 100:1 gave the best EE with the value of more than 95.0%. DCMC micelles performed an excellent ability to control the release of rotenone, of which 99.0% of rotenone was released within 48h. Overall, DCMC has several key features to be an effective carrier agent for pesticide formulations.

Layered double hydroxides and layered hydroxide salts have generated enormous excitement in the inorganic field due to their potential to act as versatile host materials in fabricating novel host–guest layered materials. The ability of the layered hydroxide anion exchanger to be incorporated with a wide range of guest ions enable them to be exploited in various applications related to pesticides. This review sums up the different methods of preparing layered hydroxide anion exchanger, summarises the types of anion intercalated into these layered hydroxide anion exchanger based on their respective systems, and elucidates their potential applications in pesticide-related fields.

Magnesium layered hydroxide (MLH) intercalated with anionic 3-(4-methoxyphenyl)propionic acid (MPP) was synthesised by a direct reaction method using magnesium oxide and MPP as precursors. A further coating of chitosan was applied on the external surface of MLH–MPP nanocomposite to form a new material, named MLH–MPP/chitosan nanocomposite. The XRD pattern showed an intense and sharp peak at basal spacing 18.9 A, proving that MPP anions were successfully intercalated into the interlayer gallery of MLH in a monolayer arrangement. The XRD pattern of the MLH–MPP/chitosan nanocomposite shows similar peaks with the MLH–MPP nanocomposite. The result was also supported by FTIR spectra and elemental analysis. TGA/DTG spectra showed that the thermal stabilities of the guest anion in the both nanocomposites were markedly enhanced. A controlled-release study of the MPP ion from the MLH–MPP/chitosan nanocomposite showed a slower release compared to MLH–MPP nanocomposite with an initial rapid release and slow r...

The article reports on a MWCNT paste electrode modified with the fenchone diazine tetracarbonylmolybdenum(0) complex, and on its application to sensitive determination of Cu(II) by using square wave anodic stripping voltammetry. Under optimal conditions and at a typical working voltage of 33 mV (vs. Ag/AgCl), response is linearly related to the concentration of Cu(II) in the 0.1 nM to 1.0 μM range, and the limit of detection is 80 pM. The relative standard deviation [for n = 5 and at a 1.0 μM concentration of Cu(II)] is 3.6 %. Unlike Pb(II), the ions Ni(II), Mg(II), Cd(II), Co(II), Hg(II), and Zn(II) do not strongly interfere. Electrochemical impedance spectroscopy reveals a fast charge transfer at the electrode-solution interface. The method was applied to the analysis of Cu(II) in water samples, and the results agreed well with those obtained by ICP-OES.

Rotenone is an active ingredient that has been widely used as pesticide. However, rotenone is poorly soluble in water. Therefore, a water-soluble carrier is needed. Here, we synthesised, characterised and applied oleoyl-carboxymethyl chitosan for the first time as a carrier agent for rotenone. Oleoyl-carboxymethyl chitosan is soluble in acidic, neutral and basic media. The critical micelle concentration of oleoyl-carboxymethyl chitosan is 0.096 mg/mL. Oleoyl-carboxymethyl chitosan formed self-aggregates and exhibited spherical shape with the values of 35.5–66.4 nm. We studied the encapsulation efficiency and loading capacity of oleoyl-carboxymethyl chitosan micelles with different weight ratios of oleoyl-carboxymethyl chitosan to rotenone. We found an encapsulation efficiency of 97 % and a loading capacity of 0.97 % for oleoyl-carboxymethyl chitosan/rotenone 100:1 w/w. Oleoyl-carboxymethyl chitosan released 96.00 % of the rotenone loaded within 50 h. Overall, our findings show the feasibility of oleoyl-carboxymethyl chitosan as a novel water-solubilising agent for pesticide formulations.

In this study, a two-step transesterification process was applied to convert crude BSF larval oil into biodiesel. The effects of methanol:oil (molar ratio), catalyst amount (weight %), reaction time (minutes) and temperature (°C) on biodiesel production were investigated. Central Composite Design (CCD) of Response Surface Methodology (RSM) was used to optimise experimental data obtained from these four variables. The prediction of biodiesel yield was made by employing a quadratic model, whereby the R2 values were greater than 0.99. Based on optimisation studies, a combination of an application of petroleum ether and reaction time of 6 hours was the best to extract crude larval oil with 47% of lipid yield. Meanwhile, methanol:oil molar ratio of 12:1, catalyst (NaOH) concentration of 1.0 weight %, a reaction time of 32 minutes and temperature of 60°C were required to obtain biodiesel with 96% of production yield from BSF crude larval oil. Both BSF crude larval oil and biodiesel were characterised using several analytical instruments such as Fourier Transform Infrared (FTIR) spectrometer and Gas Chromatography – Flame Ionisation Detector (GC-FID). Overall, findings from this study highlight the potential to produce eco-friendly biodiesel from BSF larvae reared on soya residue.

In the present work, the feasibility of chitosan-graphene oxide (CS-GO) nanocomposites, namely CS-GO 1% (w/w), CS-GO 2% (w/w) and CS-GO 3% (w/w) as water-solubilising agents for rotenone pesticide was evaluated for the first time. The CS-GO nanocomposites were characterised by using FTIR, SEM, TEM and XRD analyses. The interaction of nanocomposites with rotenone was investigated through adsorption study involving several experimental parameters such as solution pH, initial concentration and contact time. Additionally, the desorption study was carried out using HCl and NaOH as desorption agents. Based on correlation coefficient (R2), the adsorption kinetic data were best described by the pseudo-first order equation while the adsorption equilibrium data were correlated well with the Langmuir isotherm model. The GO nanoparticle aggregates have a spherical shape with size ranged from 1.40 to 34.7 nm. The crystallinity of CS was increased following interaction with GO, whereby the intensity of diffractive peak at 2θ = 20.42° was increased to more than 4000 counts. Based on Langmuir isotherm model, CS-GO 3% (w/w) exhibited the highest adsorption capacity for rotenone with Q value of 92.59 mg/g. The main mechanism for interaction of CS-GO nanocomposites with rotenone was through formation of hydrogen bond. The presence of -OH, -COOH and -NH functional groups on CS-GO nanocomposites significantly contributed to water-solubilising mechanism. The CS-GO 1% (w/w), CS-GO 2% (w/w) and CS-GO 3% (w/w) nanocomposites were able to increase the solubility of rotenone in water by 34.40%, 38.80% and 46.30%, respectively.

The study on the removal of rhodamine B under ultrasonic-assisted oxidation or called as sonocatalytic oxidation using tin oxide-immobilized onto montmorillonite (SnO2/MMT) has been investigated. A hydrothermal synthesis was used for preparing the immobilized SnO2 nanoparticles into montmorillonite structure, and the as-synthesized material was characterized using X-ray diffraction, gas sorption analysis, UV–vis diffuse reflection spectroscopy (UV–vis diffuse reflectance spectroscopy), scanning electron microscopy, and transmission electron microscopy techniques. The kinetics study of the sonocatalytic-assisted oxidation was performed by the comparison with SnO2 and MMT, and in order to discover the kinetic characteristics of the sonocatalytic oxidation, varied condition such as the effect of initial concentration of rhodamine B, pH, the addition of H2O2 were examined. The proposed kinetic model revealed that the degradation obeys the apparent first-order rate kinetics. Refer to the dependence of the kinetics reaction to the initial concentration rhodamine B and H2O2 concentration, it is noted that the reaction fit with the Langmuir and Okitsu model suggesting that the sonocatalytic mechanism is influenced by active interface interaction for the cavitation and radical formation as the main operational parameters. pH of the solution directly influences the initial rate of the reaction as the effect of zeta potential of the surface. Reusability study revealed that the catalyst maintains the stability until 3 cycles utilization with the maximum degradation efficiency of ∼100 % under the condition of ultrasound frequency of 40 W, 68 kHz, catalyst dose of 0.5 g/L, and reaction time of 2 h.

This study involves the preparation of hematite/biochar (HBC) nanocomposite and its photocatalytic evaluation for methylene blue degradation. HBC material was synthesized based on carbonization of iron oxide precursor-treated Salacca skin powder. Characterization studies of the material were carried out using x-ray diffraction, scanning electron microscope-energy dispersive x-ray, transmission electron microscope, and gas sorption analysis. Dispersed Fe2O3 with sizes ranging from 20 to 50 nm in the nanocomposite were identified, showing a band gap energy of 2.21 eV. Results show that the material demonstrates suitable physicochemical performance for photocatalytic application. By varying the initial concentration of methylene blue, it is noted that the decolorization obeys pseudo-first-order kinetics and fits the Langmuir-Hinshelwood mechanism. The decolorization kinetics was observed to be at optimum level at pH 7, reaching this state with a catalyst dosage of 0.5 g/L. The performance of the photocatalyst was observed to be better with H2O2 addition, in which the decolorization efficiencies reach 99.9% for all varied initial concentrations with 1 h treatment.

In this work, chitosan, gelatin and methylcellulose films incorporated with tannic acid (TA) were synthesised, characterised and applied for the first time to preserve cherry tomatoes (Solanum lycopersicum var. cerasiforme) and grapes (Vitis vinifera). The addition of TA at 15% (w/w) increased the transparency value of biopolymer films. The highest increment of transparency value was obtained for MC-TA film, increased from 0.572 to 4.73 A/mm. Based on antimicrobial study, the addition of TA improved the antibacterial properties of biopolymers against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). The ability of films to preserve both fruits was evaluated in a 14-day preservation study. The application of biopolymer films treated with TA has decreased the weight loss and browning index of fruits, as compared to control films. A significant reduction in the weight loss of cherry tomatoes wrapped with chitosan (from 21.3 to 19.6%), gelatin (from 22.1 to 15.5%) and methylcellulose (26.2 to 20.5%) films were obtained following TA treatment. Overall, results obtained from this study highlight the effects of TA on physiochemical properties of biopolymer films and their ability to preserve fruits.