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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.

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.

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.

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.

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.

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...

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.

For the first time, amorphous aluminium–copper (Al–Cu) alloy nanowires decorated with carbon spheres (CS) were synthesised from waste engine oil (WEO) as a starting material. The synthesis process was carried out in two-stage thermal chemical vapour deposition system under typical synthesis condition of 5.33 wt% ferrocene as catalyst, precursor and synthesis temperature of 450 and 700 °C, respectively. Metal contaminants of Al and Cu in WEO promote the growth of amorphous Al–Cu alloy nanowires and high carbon content in WEO undeniable promotes the growth of CS. Field emission scanning electron microscopy analysis showed that the amorphous Al–Cu alloy nanowires dimension was about 120 nm in diameter and a few micrometres in length, while the diameter of CS were a few hundred nanometre to micrometre-sized. X-ray diffraction pattern of amorphous Al–Cu alloy nanowires revealed the formation of different Al–Cu phases. This study offers a new and simple technique to synthesise amorphous Al–Cu alloy nanowires decorated with CS from waste material namely WEO. The newly produced nanomaterials open up potential application in energy storage devices.

Zn/Al layered double hydroxide (LDH) intercalated by an anionic phenoxyherbicide guest, 3-(4-methoxypheny) propionate (MPP) were prepared by ion-exchange method. Power XRD and FTIR shows that the MPP phenoxyherbicide were successfully intercalated into the LDH interlayer. The basal spacing for Zn/Al layered double hydroxide-3-(4-methoxyphenyl) propionate nanocomposite (LDH-MPP) was 18.7 Å - 20.5 Å for 0.015 M, 0.025 M, and 0.050 M of MPP, respectively. Thermal analysis shows that the thermal stability of MPP was improved by the intercalation into the LDH interlayer. The results were also supported by elemental analysis and the surface morphology of this nanocomposite.

The performance of single-, double- and triple-chain anionic sulphosuccinate surfactants for dispersing multiwall carbon nanotubes (MWNCTs) in natural rubber latex (NR-latex) was studied using a range of techniques, including field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), thermogravimetric analysis (TGA) and Raman spectroscopy. The conductivities of the nanocomposites were also investigated using four-point probe measurements. Here, MWCNTs were efficiently dispersed in NR-latex with the aid of hyperbranched tri-chain sulphosuccinate anionic surfactants, specifically sodium 1,4-bis(neopentyloxy)-3-(neopentyloxycarbonyl)-1,4-dioxobutane-2-sulphonate (TC14). This paper highlights that TC14 performs much better than that of the commercially available surfactant sodium dodecyl sulphate (SDS), demonstrating how careful consideration of surfactant architecture leads to improved dispersibility of MWCNTs in NR-latex. The results should be of significant interest for improving nanowiring applications suitable for aerospace-based technology.

A new layered-double hydroxide-3-(4-hydroxyphenyl) propionate (LDH-HPP) has been synthesized by intercalation of 3-(4-hydroxyphenyl) propionic acid (HPP) into Zn-Al-layered double hydroxide (LDH) by ion-exchange method. PXRD, FTIR, TGA/DTG, compositional studies and FESEM were used to characterize the synthesized nanocomposite. The intercalation of HPP into the interlayer gallery space of LDH was characterized by x-ray diffractogram showed expanded basal spacing of the value of 17.1 Å. The FTIR spectra of LDH-HPP nanocomposite synthesis by 0.025M HPP resembled a mixture of both FTIR spectra of HPP and LDH. Thermal analysis of LDH-HPP nanocomposite shows a better thermal stability as compared to the pure HPP, which proved that the intercalation of HPP into LDH interlayer enhanced the thermal stability of the HPP.

Thymol is a hydrophobic active ingredient and widely used as an alternative pesticide for pest control. However, due its low solubility in water, a water-soluble carrier is required in its formulation. Therefore in this study, the potential of an amphiphilic chitosan, namely lauryl glycol chitosan (LGC) as a carrier to encapsulate and release thymol was evaluated. The physical and chemical properties of LGC were characterized using Fourier Transform Infrared (FTIR) Spectrometer, Proton Nuclear Magnetic Resonance (1H NMR) Spectrometer, UV-Visible Spectrophotometer, Thermogravimetric Analyser (TGA) and Transmission Electron Microscope (TEM). A Fluorescence Spectrometer was used to determine the critical micelle concentration (CMC) value of LGC in aqueous solution. The encapsulation efficiency of LGC for thymol was determined by using a High Performance Liquid Chromatography (HPLC). The FTIR and 1H NMR analyses confirmed the structure of the synthesized LGC. It was noted that the addition of lauryl and glycol groups to the chitosan backbone has enhanced the solubility properties of chitosan in neutral and basic media. TEM observation confirmed that LGC could form self-aggregates in the solution with a spherical shape. The CMC value determined for LGC was 0.008 mg/mL. LGC exhibited good affinity towards thymol with an encapsulation efficiency of 58%. The findings from in vitro release study showed that the LGC could prolong the release of thymol from its micelles. Results from this study highlight that LGC possesses great characteristics to be further developed as a promising carrier in the pesticide formulation.

Dyes are stable organic pollutants that have been used in many industries and become one of the toxic contaminants for the environment. This research aimed at preparing a magnetic chitosan nanocomposite (MCN) as an effective adsorbent for cationic and anionic dye removal from aqueous solution. The MCN was synthesized using a coprecipitation method. The physical properties of MCN were characterized using elemental analysis (CHNO), vibrating sample magnetometry (VSM), scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and X-ray diffractometry (XRD). The results confirm that chitosan has been embedded on the surface of magnetic material and shows superparamagnetic properties behavior. A series of adsorption were conducted to investigate dosage of adsorbent, contact time and initial dye concentration to obtain the optimum condition of adsorption for both methylene blue (MB) and congo red (CR) dyes. The experimental equilibrium adsorption were then analyzed by the Langmuir and Freundlich isotherm models. Based on the correlation coefficient (R 2) values, the equilibrium adsorption data were fitted to the Langmuir isotherm model. The maximum adsorption capacity (q m) obtained from the Langmuir isotherm model for MB and CR onto MCN was 0.1308 and 1.8257 mg/g, respectively. Results highlight the potential of MCN application as an adsorbent for water contaminated by dyes.

In this study, Ca-ZSM-5 zeolite nanocomposite was synthesised as controlled-released fertiliser due to the excess of nutrients leaching in the soil which has caused serious environmental problem such as eutrophication. The zeolite nanocomposite was first synthesised using a simple co-precipitation template method. The zeolite nanocomposite was then impregnated with calcium, originated from chicken eggshell powder, at a molar ratio of 1:1. The physical and chemical properties of Ca-ZSM-5 zeolite nanocomposite were characterised using several analytical instruments such as Fourier Transform Infrared (FTIR) Spectrometer, Scanning Electron Microscope (SEM), Energy Dispersive X-ray (EDX) Spectrometer and Transmission Electron Microscopy (TEM). Based on SEM analysis, the porosity of mesoporous H-ZSM-5 nanozeolite was in the range of 31.7 to 190 nm. Meanwhile, the porosity of macroporous eggshell was 71.4 to 230 nm and mesoporous H-ZSM-5 nanozeolite material was impregnated into the macroporous eggshell due to porosity of eggshell was larger than porosity of H-ZSM-5 nanozeolite. Ca-ZSM-5 zeolite nanocomposite with porosity of 71.4-198 nm was successfully synthesised by simple co-precipitation method. While the results obtained from FTIR analysis confirmed the presence of tetrahedral (TOx, x = Si or Al) stretching. Overall, the synthesised Ca-ZSM-5 zeolite nanocomposite possess key characteristic as a precursor for various applications.

The overall objective of present work was to prepare and use chitosan-titanium dioxide (CS-TiO2) nanocomposite as an adsorbent to remove two toxic dyes, namely Methyl Orange (MO) and Rhodamine B (RhB) from the aqueous solution. This work consists of two main parts, namely adsorption and characterization studies. For adsorption studies, several experimental parameters were studied such as the effect of initial concentration, solution pH and adsorbent dosage. Meanwile, Scanning Electron Microscope (SEM), Thermogravimetric Analyser (TGA), and X-ray Diffractometer (XRD) were used for characterization studies. The outcomes have shown that the equilibrium data correlated well to Freundlich isotherm model with adsorption capacity at equilibrium (K F) was determined as 1.608 mg/g for MO and 7.646 mg/g for RhB, respectively. Based on SEM analysis, the rod- and needle-like deposits on the surface of CS-TiO2 nanocomposite were disappeared following interaction with MO and RhB. There were cube-like deposits observed on the surface of CS-TiO2 nanocomposite after adsorption of MO, while a dense and uneven surface texture were observed after adsorption of RhB. From TGA analysis, CS had two degradation stages, while CS-TiO2 nanocomposite had three steps of decomposition. Furthermore, XRD results observed diffraction peaks for CSTiO2 at 2θ = 34.075°, 29.235°, 25.47° and 20.26°.

Mosquito-borne diseases are great concerns of people in the worldwide, especially dengue. There are 390 million people infected with dengue in a year. According to Dengue Situation Update Report for Western Pacific Region, there is an increment in the number of the infected areas as compared to the same period of previous year. World of Health Organization (WHO) and Ministry of Health (MOH) from every country pay the highest attention towards this issue. Other than inventing new formulation of adulticides, application of larvicide is newly emerging as an effective method to control mosquitoes from spreading virus. In this brief review, several recent studies about ways of the virus transmitted through mosquito biting behaviour, larvicide formulation and types of carrier agents being used to carry larvicide will be discussed. In order to sustain the aquatic ecosystem, materials for carrier agents should be environmental-friendly. This review paper will give insight into the recent development in carrier system for mosquitoes larvicide formulations.

Two phenoxyherbicide nanocomposites, namely cloprop-layered double hydroxide and cloprop-zinc- layered hydroxide nanocomposites, have been synthesized by using co-precipitation and direct reaction method. PXRD pattern showed an expansion of interlayer spacing with the value of 21.0 A and 22.7 A for cloprop-layered double hydroxide and cloprop-zinc-layered hydroxide nanocomposite, respectively. It is evident from FTIR and elemental analyses that both nanocomposites were successfully intercalated between the interlayers of layered metal hydroxide. Controlled release of cloprop anion from interlayer of nanocomposites for both cloprop-layered double hydroxide and cloprop-zinc-layered hydroxide nanocomposite into phosphate solution was rapid initially and slow thereafter. The percentage of accumulated release of cloprop anion from cloprop-zinc-layered hydroxide nanocomposite was slightly higher than that from cloprop-layered double hydroxide nanocomposite. Kinetic behavior of cloprop release was governed by pseudo-second-order for cloprop-layered double hydroxide nanocomposite while parabolic diffusion for cloprop-zinc-layered hydroxide nanocomposite. Results from this study highlight the potential of both nanocomposites as capsulated material for controlled release of cloprop phenoxyherbicides anion.

The feasibility of durian tree sawdust (DTS), coconut coir (CC) and oil palm empty fruit bunch (EFB) as low-cost biosorbents for the removal of Cu(II), Pb(II) and Zn(II) ions from aqueous solutions was investigated. The effects of solution pH and initial metal concentration on adsorption capacity were examined in batch experiments. The affinity and the adsorption capacity of DTS, CC and EFB were evaluated. The adsorption behaviour of Cu(II), Pb(II) and Zn(II) ions onto DTS, CC and EFB was described using Freundlich and Langmuir isotherm models. The separation factor (RL) analysis suggests that the removal of metal ions onto three agricultural wastes studied was favourable. The maximum adsorption capacities (Q) estimated from the Langmuir isotherm model for Cu(II), Pb(II) and Zn(II) were 18.42, 20.37 and 22.78 mg/g for DTS, 18.38, 37.04 and 24.39 mg/g for CC, and 26.95, 37.59 and 21.19 mg/g for EFB, respectively. The characterisation studies were carried out using Scanning Electron Microscope (SEM), Energy Dispersive X-ray Spectrometer (EDX) and Fourier Transform Infrared Spectrometer (FTIR). The surface morphology of the biosorbents changed significantly following interaction with metal ions. The primary adsorption mechanism was complexation between metal ions and binding sites of biosorbents. Both hydroxyl and amine groups are the main binding sites in DTS, CC and EFB.

The efficacy of coconut tree sawdust (CTS), eggshell (ES) and sugarcane bagasse (SB) as alternative low-cost biosorbents for the removal of Cu(II), Pb(II) and Zn(II) ions from aqueous solutions was investigated. Batch adsorption studies were carried out to evaluate the effects of solution pH and initial metal concentration on adsorption capacity. The optimum biosorption condition was found at pH 6.0, 0.1 g biomass dosage and at 90 min equilibrium time. The adsorption data were fitted to the Freundlich and Langmuir isotherm models. The adsorption capacity and affinity of CTS, ES and SB were evaluated. The Freundlich constant (n) and separation factor (RL) values suggest that the metal ions were favourably adsorbed onto biosorbents. The maximum adsorption capacities (Q) estimated from the Langmuir isotherm model for Cu(II), Pb(II) and Zn(II) were 3.89, 25.00 and 23.81 mg/g for CTS, 34.48, 90.90 and 35.71 mg/g for ES, and 3.65, 21.28 and 40.00 mg/g for SB, respectively. The characterisation studies were performed using Scanning Electron Microscope (SEM), Energy Dispersive X-ray Spectrometer (EDX) and Fourier Transform Infrared Spectrometer (FTIR). Interaction with metal ions led to the formation of discrete aggregates on the biosorbents surface. The metal ions bound to the active sites of the biosorbents through either electrostatic attraction or complexation mechanism.

The concentrations of Al, As, Cd, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Sn and Zn were analysed in water, sediment, muscle of climbing perch fish (Anabas testudineus), and tissue of water hyacinth plants (Eichhornia crassipes) collected from a former tin-mining pond in Perak, Malaysia. The monitoring was performed during the minimum and maximum rainfall periods. The concentrations of As, Cr, Fe, Ni, Pb and Zn in water exceeded the permissible limits set by the Interim National Water Quality Standards for Malaysia (INWQS). The risk index (RI) values determined for As, Cd, Cr, Cu, Hg, Pb and Zn in sediment presented a low degree of ecological risk. The order of the top three heavy metals measured in fish muscle was Zn > Fe > Al. The estimated daily intake (EDI) of As and Cr exceeded the allowable limits in both rainfall periods. The bioconcentration factor (BCF) and translocation factor (TF) values of Zn in water hyacinth were 24.865 and 3.214, respectively. The concentrations of Cu and Zn in the plant tissue were significantly correlated (p < .05) with the concentrations of heavy metals in water. Overall, climbing perch and water hyacinth are excellent bioindicators of environmental impacts on water bodies.

In the present study, the feasibility of amphiphilic chitosan derivatives, namely oleoyl carboxymethyl chitosan (OCMCs), N,N-dimethylhexadecyl carboxymethyl chitosan (DCMCs) and deoxycholic acid carboxymethyl chitosan (DACMCs) as carrier agents for rotenone in water-insoluble pesticide formulations was investigated. Fourier Transform Infrared (FTIR) Spectrometer, CHN-O Elemental Analyser (CHN-O) and Transmission Electron Microscope (TEM) were used to characterise amphiphilic chitosan derivatives. The critical micelle concentration (CMC) of amphiphilic chitosan derivatives was determined using a Fluorescence Spectrometer. A High Performance Liquid Chromatography (HPLC) was used to determine the ability of OCMCs, DCMCs and DACMCs to load and release rotenone in an in vitro system. Based on TEM analysis, results have shown that amphiphilic chitosan derivatives formed self-assembly and exhibited spherical shape. The CMC values determined for OCMCs, DCMCs and DACMCs were 0.093, 0.098 and 0.468 mg/mL, respectively. The encapsulation efficiency (EE) values for the materials were more than 97.0%, meanwhile the loading capacity (LC) values were greater than 0.90%. OCMCs, DCMCs and DACMCs micelles exhibited an excellent ability to control the release of rotenone, of which 90.0% of rotenone was released within 40 to 52 h. In conclusion, OCMCs, DCMCs and DACMCs possess several key features to act as effective carrier agents for rotenone. Overall, amphiphilic chitosan derivatives produced in this study were successfully increased the solubility of rotenone by 49.0 times higher than free rotenone.In the present study, the feasibility of amphiphilic chitosan derivatives, namely oleoyl carboxymethyl chitosan (OCMCs), N,N-dimethylhexadecyl carboxymethyl chitosan (DCMCs) and deoxycholic acid carboxymethyl chitosan (DACMCs) as carrier agents for rotenone in water-insoluble pesticide formulations was investigated. Fourier Transform Infrared (FTIR) Spectrometer, CHN-O Elemental Analyser (CHN-O) and Transmission Electron Microscope (TEM) were used to characterise amphiphilic chitosan derivatives. The critical micelle concentration (CMC) of amphiphilic chitosan derivatives was determined using a Fluorescence Spectrometer. A High Performance Liquid Chromatography (HPLC) was used to determine the ability of OCMCs, DCMCs and DACMCs to load and release rotenone in an in vitro system. Based on TEM analysis, results have shown that amphiphilic chitosan derivatives formed self-assembly and exhibited spherical shape. The CMC values determined for OCMCs, DCMCs and DACMCs were 0.093, 0.098 and 0.468 mg/mL, respectiv...

The binding efficiency of chitosan samples for Ag(+), Cd(2+), Cu(2+), Pb(2+) and Zn(2+) has been evaluated in order to consider their application to remediate metal contaminated soil and water. The sorption behaviour of metal ions was assessed using a batch technique at different contact time and initial metal concentration with different background electrolytes. The kinetics followed a pseudo-second-order model, while the equilibrium data correlated well with the Freundlich and Langmuir isotherm models. For example, the maximum sorption capacity (Q) for chitosan was estimated as 1.93 mmol/g for Ag(+), 1.61 mmol/g for Cu(2+), 0.94 mmol/g for Zn(2+), 0.72 mmol/g for Cd(2+) and 0.64 mmol/g for Pb(2+). Covalent interaction between metal ions and functional groups (amino and hydroxyl) of the chitosans was the main binding mechanism. Ion exchange is not an important process. Chitosan and cross-linked chitosans were able to bind metal ions in the presence of K(+), Cl(-) and NO(3)(-). The nature of Cl(-) and NO(3)(-) ions did not affect Zn(2+) binding by the chitosans. Even at 11x dilution, the chitosans were able to retain metal ions on their surfaces.

In this study, [Ir(2,4-F2ppy)2(2-(1,2,4-triazol-1-yl)pyridine>)]PF6 (C1), [Ir(2,4-F2ppy)2(2-(2-(4-dimethylbenzyl)-1,2,4-triazol-1-yl)pyridine)]PF6 (C2) and [Ir(2,4-F2ppy)2(2(2-hexyl-1,2,4-triazol-1-yl)pyridine)]PF6 (C3) complexes were successfully synthesised by refluxing the mixture of dichloro-bridged iridium(III) dimer, [Ir(2,4-F2ppy)2(μ-Cl)]2 and corresponding triazolium salt containing N-heterocyclic carbene (NHC) as ancillary ligands. 1H NMR of all complexes display well-resolved signals between 10.00-5.00 ppm assign to proton at the aromatic region for penylpyridine and pyridyltriazole. Spectra of C2 and C3 also display signals at aliphatic region (singlets) between 0.80-1.50 ppm that proved the presence of methylbenzyl and hexyl substituent on the pyridyltriazole ring. In addition, IR analysis reported the presence of C=C and C=N stretching of pyridine at range 1570-1470cm−1 and C-H stretching of aromatic pyridine at 2990-3080cm−1. Besides, UV-Vis absorption data showed that the low-energy metal-to-ligand charge-transfer (MLCT) band in C2 (364 nm) is significantly blue-shifted compared to C1 (375 nm) and C3 (381 nm). Overall, this study reported the synthesis and spectroscopic study of phenylpyridine Ir(III) complexes with various types of pyridyltriazole (NHC ancillary ligands).

Lipid enhancement is important to reduce production cost thus increasing the commercial values of microalgal biofuel production. Physical stress such as temperature and light intensity are known to increase lipid productivity because these factors might affect the phase transition of lipid, macromolecule formation and physiochemical reactions of microalgae. In this study, the effect of light intensity and temperature on lipid productivity of Tetradesmus obliquus was studied. T.obliquus UPSI-JRM02 was cultured in BG11 media at different temperature range (25–40°C) and light intensity (4000–30000 lux), respectively, within 14 days of growth period. The highest lipid productivity was obtained at temperature and light intensity of 36°C and 23500 lux. At this condition, 27 mg/L/day of lipid productivity and 23% of total lipid was successfully produced. The result shows the possibility of increasing T.obliquus lipid productivity by giving physical stress to the cell.

The kinetic and thermodynamic adsorption and adsorption isotherms of Pb(II) and Cu(II) ions onto H(2)SO(4) modified chitosan were studied in a batch adsorption system. The experimental results were fitted using Freundlich, Langmuir and Dubinin-Radushkevich isotherms; the Langmuir isotherm showed the best conformity to the equilibrium data. The pseudo-first order, pseudo-second order and intraparticle diffusion kinetic models were employed to analyze the kinetic data. The adsorption behavior of Pb(II) and Cu(II) was best described by the pseudo-second order model. Thermodynamic parameters such as free energy change (DeltaG degrees ), enthalpy change (DeltaH degrees ) and entropy change (DeltaS degrees ) were determined; the adsorption process was found to be both spontaneous and exothermic. No physical damage to the adsorbents was observed after three cycles of adsorption/desorption using EDTA and HCl as eluents. The mechanistic pathway of the Pb(II) and Cu(II) uptake was examined by means of Fourier transform infrared (FTIR) and Energy dispersive X-ray (EDX) spectroscopy. The equilibrium parameter (R(L)) indicated that chitosan-H(2)SO(4) was favorable for Pb(II) and Cu(II) adsorption.

The relationship between the tail architecture and performance of hybrid AOT analogue surfactants has been investigated. Three hybrid surfactants were synthesised using hydrocarbon CO2-philic tails with different levels of chain branching. The performance of each surfactant was investigated via high-pressure phase behaviour, UV-visible spectroscopy, and air–water (a/w) surface tension measurements. Notably, the incorporation of hydrocarbon CO2-philic tails with a high degree of branching has been found to significantly boost CO2-philicity, allowing the surfactant to stabilise water-in-CO2 (w/c) microemulsions at low cloud pressures, Ptrans. The newly synthesised hybrid CF2/SIS1 (sodium (4H, 4H, 5H, 5H, 5H-pentafluoropenyl-5,7,7-trimethyl-2-(1,3,3-trimethyl-buthyl)-octyl)-2-sulfosuccinate) is a CO2-philic surfactant that contains the lowest amount of fluorine (15.01 wt%) and exhibits the highest efficiency of any di-chain surfactant to date. High-pressure phase behaviour studies provided a maximum water-to-surfactant molar ratio (wmax) of wmax = 39, which is usually only observed from surfactants with long fluorocarbon chains. The present results are beneficial for expanding the pool of economical, effective, and efficient surfactants available for CO2-based technology.

A basic investigation on the removal of Cr(III) and Cr(VI) ions from aqueous solution by chitosan beads was conducted in a batch adsorption system. The chitosan beads were prepared by casting an acidic chitosan solution into an alkaline solution. The influence of different experimental parameters; pH, agitation period and different concentration of Cr(III) and Cr(VI) ions was evaluated. A pH 5.0 was found to be an optimum pH for Cr(III) adsorption, and meanwhile pH 3.0 was the optimum pH for the adsorption of Cr(VI) onto chitosan beads. The Langmuir and Freundlich adsorption isotherm models were applied to describe the isotherms and isotherm constants for the adsorption of Cr(III) and Cr(VI) onto chitosan beads. Results indicated that Cr(III) and Cr(VI) uptake could be described by the Langmuir adsorption model. The maximum adsorption capacities of Cr(III) and Cr(VI) ions onto chitosan beads were 30.03 and 76.92 mg g−1, respectively. Results showed that chitosan beads are favourable adsorbents. The Cr(III) and Cr(VI) ions can be removed from the chitosan beads by treatment with an aqueous EDTA solution.

The potential of chitosan, a fishery waste-based material, as a soil amendment to clean-up metal contaminated soil was investigated. Chitosan was treated using glutaraldehyde (GLA), epichlorohydrin (ECH) and ethylene glycol diglycidyl ether (EGDE) as cross-linking reagents to enhance its chemical stability in acidic media and to improve its physical properties. Cross-linking treatment had significant effects on chitosan surface area, pore diameter, surface morphology and crystallinity. Interaction with Ag(I), Pb(II) and Cu(II) decreased the crystallinity of the materials and changed their surface morphology significantly. FTIR analysis confirmed that N and O atoms served as binding sites for the metal ions. Chitosan and treated chitosans were able to bind metal ions, even in the presence of K(+), Cl(-) and NO(3)(-), which are dominant ions in soil. Therefore, remediation of metal contaminated soil using chitosan and cross-linked treated chitosans as soil amendments is feasible.