Combination of gamma irradiation and sodium carbonate pretreatment on oil palm Empty Fruit Bunch (EFB) for high acidic hydrolysis yield

Oil palm empty fruit bunch (EFB) fibres were pretreated by gamma irradiation followed by sodium carbonate (Na2CO3) before the acid hydrolysis process to produce reducing sugars using diluted sulphuric acid (H2SO4). In this study, EFB fibres were irradiated at different doses, i.e. 0, 100 and 200 kGy. Meanwhile, the gamma irradiated sample were then subjected to Na2CO3 pretreatment with 0 and 5% total titratable alkali (TTA). The effect of the pretreatment using gamma irradiation and Na2CO3 on the physical and chemical properties of the EFB fibres and the yield of the reducing sugar obtained from the acid hydrolysis process was investigated. The obtained results showed that the content of holocellulose was increased significantly with the increase of irradiation doses combined with Na2CO3 pretreatment, whereas lignin content of the EFB was decreased. The gamma irradiation and Na2CO3 pretreatment resulted in structure breakage and removal of silica of EFB fibres which can be due to the swelling of the fibres. A synergistic effect between gamma irradiation and Na2CO3 was observed, in which the yield of reducing sugars was increased by combining the gamma irradiation and Na2CO3 pretreatment

Puncture resistance and mechanical properties of graphene oxide reinforced natural rubber latex

Natural rubber (NR) latex gloves are widely used as a very important barrier for healthcare workers. However, they can still be perforated easily by sharp devices and instruments. The aim of this study was to investigate the effect of the addition of graphene oxide (GO) to low-ammonia NR latex on its puncture resistance, mechanical properties and thermal stability. GO was synthesized using modified Hummers’ reaction. The produced GO was mixed into the NR latex solution at various doses (0.01-1.0 wt. %), followed by a coagulant dipping process using ceramic plates to produce film samples. Puncture resistance was enhanced by 12% with 1.0 wt. % GO/NR. Also, the incorporation of GO improved the stress at 300% and 500%, the modulus at 300% and 500% and the tear strength of low-ammonia NR latex films

Comparative adsorption mechanism of rice straw activated carbon activated with NaOH and KOH

Activated carbon (AC) was produced from rice straw via a two-step method. Potassium hydroxide (KOH) and sodium hydroxide (NaOH) were used as activating agent. The activated carbon (AC) samples were used as adsorbent to remove methylene blue (MB) from aqueous solution. Characterizations using a scanning electron microscope (SEM), BrunauerEmmett-Teller surface area (BET), and Fourier transform infrared (FTIR) spectroscopy were performed on the samples before the MB adsorption experiments. The adsorption isotherms and kinetics analyses were carried out under different conditions of pH, temperature, and MB concentration to study the adsorption efficiency of the samples against the MB solution. The adsorption kinetics of both activated carbon samples followed the pseudo-second-order model. The adsorption capacity of the KOH rice straw activated carbon towards MB achieved a maximum adsorption 588 mg/g as compared to 232 mg/g of the NaOH rice straw activated carbon. The intraparticle diffusion model indicated that the adsorption process of the activated carbon samples toward MB included the external mass transfer and diffusion of MB molecules into the adsorbents. Adsorption isotherm results for MB on the activated carbon samples fit the Langmuir isotherm, suggesting monolayer adsorption during the adsorption process

Silver nanowires as flexible transparent electrode: role of PVP chain length

In this project, crystalline silver nanowires (AgNWs) are successfully grown using a continuous segmented flow process. The robust relationship among the structural, electrical and optical properties of the AgNWs in the function of the polyvinylpyrrolidone (PVP) chain length is elaborated. A concise carrier transport and a density mechanism are also discussed using a localized conductive atomic force microscopy analysis. The obtained results proved that the AgNWs synthesized using PVP with a chain length of 1.3 M exhibit excellent electrical and optical properties in the form of flexible transparent film with a sheet resistance of 90% at various bending angles. These findings present an alternative approach for production of AgNWs and fabrication of a high flexible transparent electrode

Chitosan Fibers Loaded with Limonite as a Catalyst for the Decolorization of Methylene Blue via a Persulfate-Based Advanced Oxidation Process

Wastewater generated from industries seriously impacts the environment. Conventional biological and physiochemical treatment methods for wastewater containing organic molecules have some limitations. Therefore, identifying other alternative methods or processes that are more suitable to degrade organic molecules and lower chemical oxygen demand (COD) in wastewater is necessary. Heterogeneous Fenton processes and persulfate (PS) oxidation are advanced oxidation processes (AOPs) that degrade organic pollutants via reactive radical species. Therefore, in this study, limonite powder was incorporated into porous regenerated chitosan fibers and further used as a heterogeneous catalyst to decompose methylene blue (MB) via sulfate radical-based AOPs. Limonite was used as a heterogeneous catalyst in this process to generate the persulfate radicals (SO4−·) that initiate the decolorization process. Limonite–chitosan fibers were produced to effectively recover the limonite powder so that the catalyst can be reused repeatedly. The formation of limonite–chitosan fibers viewed under a field emission scanning electron microscope (FESEM) showed that the limonite powder was well distributed in both the surface and cross-section area. The effectiveness of limonite–chitosan fibers as a catalyst under PS activation achieved an MB decolorization of 78% after 14 min. The stability and reusability of chitosan–limonite fibers were evaluated and measured in cycles 1 to 10 under optimal conditions. After 10 cycles of repeated use, the limonite–chitosan fiber maintained its performance up to 86%, revealing that limonite-containing chitosan fibers are a promising reusable catalyst material

Combination of Gamma Irradiation and Sodium Carbonate Pretreatment on Oil Palm Empty Fruit Bunch (EFB) for High Acidic Hydrolysis Yield

Oil palm empty fruit bunch (EFB) fibres were pretreated by gamma irradiation followed by sodium carbonate (Na2CO3) before the acid hydrolysis process to produce reducing sugars using diluted sulphuric acid (H2SO4). In this study, EFB fibres were irradiated at different doses, i.e. 0, 100 and 200 kGy. Meanwhile, the gamma irradiated sample were then subjected to Na2CO3 pretreatment with 0 and 5% total titratable alkali (TTA). The effect of the pretreatment using gamma irradiation and Na2CO3 on the physical and chemical properties of the EFB fibres and the yield of the reducing sugar obtained from the acid hydrolysis process was investigated. The obtained results showed that the content of holocellulose was increased significantly with the increase of irradiation doses combined with Na2CO3 pretreatment, whereas lignin content of the EFB was decreased. The gamma irradiation and Na2CO3 pretreatment resulted in structure breakage and removal of silica of EFB fibres which can be due to the swelling of the fibres. A synergistic effect between gamma irradiation and Na2CO3 was observed, in which the yield of reducing sugars was increased by combining the gamma irradiation and Na2CO3 pretreatment

Rapid Catalytic Reduction of 4-Nitrophenol and Clock Reaction of Methylene Blue using Copper Nanowires

Copper nanowires (CuNWs) with a high aspect ratio of ~2600 have been successfully synthesized by using a facile hydrothermal method. The reductions of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) and methylene blue (MB) to leucomethylene blue (LMB) by using sodium borohydride (NaBH4) were used as models to test the catalytic activity of CuNWs. We showed that by increasing the CuNWs content, the rate of reduction increased as well. The CuNWs showed an excellent catalytic performance where 99% reduction of 4-NP to 4-AP occurred in just 60 s by using only 0.1 pg of CuNWs after treatment with glacial acetic acid (GAA). The rate constant (kapp) and activity factor (K) of this study is 18 and ~1010 fold in comparison to previous study done with no GAA treatment applied, respectively. The CuNWs showed an outstanding catalytic activity for at least ten consecutive reusability tests with a consistent result in 4-NP reduction. In clock reaction of MB, approximately 99% of reduction of MB into LMB was achieved in ~5 s by using 2 μg CuNWs. Moreover, the addition of NaOH can improve the rate and degree of recolorization of LMB to MB

Conversion of glucose into lactic acid using silica-supported zinc oxide as solid acid catalyst

Zinc oxide (ZnO) has been proven to be highly effective in converting biomass into fine chemicals. It possesses several limitations, such as leaching in hydrothermal reactions and difficulty with regard to its recovery. Supporting ZnO on silica improves its recovery, stability and recyclability. In this study, we produced silica-supported ZnO by incipient wetness impregnation (IWI) method for the conversion of glucose into lactic acid. The presence of the ZnO provided active sites for isomerization to occur. The highest yield of lactic acid was 39.2 % at 180 °C for 60 min. Prolonged reaction time and higher reaction temperature promoted further degradation of lactic acid into acetic acid. The yield of lactic acid decreased after the first cycle and decreased slightly for the nine consecutive cycles

Biogenic Synthesis of Copper-Based Nanomaterials Using Plant Extracts and Their Applications: Current and Future Directions

Plants have been used for multiple purposes over thousands of years in various applications such as traditional Chinese medicine and Ayurveda. More recently, the special properties of phytochemicals within plant extracts have spurred researchers to pursue interdisciplinary studies uniting nanotechnology and biotechnology. Plant-mediated green synthesis of nanomaterials utilises the phytochemicals in plant extracts to produce nanomaterials. Previous publications have demonstrated that diverse types of nanomaterials can be produced from extracts of numerous plant components. This review aims to cover in detail the use of plant extracts to produce copper (Cu)-based nanomaterials, along with their robust applications. The working principles of plant-mediated Cu-based nanomaterials in biomedical and environmental applications are also addressed. In addition, it discusses potential biotechnological solutions and new applications and research directions concerning plant-mediated Cu-based nanomaterials that are yet to be discovered so as to realise the full potential of the plant-mediated green synthesis of nanomaterials in industrial-scale production and wider applications. This review provides readers with comprehensive information, guidance, and future research directions concerning: (1) plant extraction, (2) plant-mediated synthesis of Cu-based nanomaterials, (3) the applications of plant-mediated Cu-based nanomaterials in biomedical and environmental remediation, and (4) future research directions in this area

Study on effect of toluene-acid treatments of recycled carbon black from waste tyres: physico-chemical analyses and adsorption performance

Recycled carbon black (rCB) produced by pyrolysis has a low value because it contains high levels of impurities, such as sulfur, nitrogen, and oxygen. Various treatments have been proposed using chemicals to purify and improve the properties of rCB. In this study, rCB was treated with toluene (rCB-T), followed by subsequent treatment using acids HCl (rCB-T-HCl), HNO3 (rCB-T-HNO3 ), and HCl-HNO3 (rCB-T-HCl-HNO3 ). The treated rCB samples were characterized using CHNS analyser, scanning electron microscope, BET analyser, zeta potential, Fourier transform infrared spectroscopy, and Raman spectroscopy. The adsorption of methylene blue dye onto the rCB samples was also investigated to study the effectiveness of the treatments. Treatment with toluene alone was insufficient to increase the carbon content and surface area of the rCB. Subsequent treatment of rCB with acids, especially HNO3 , significantly increases the carbon content, surface area, surface functional groups, and surface charge of the rCB. This results in an increased adsorption capacity of the rCB, from 6.04 mg/g to 46.51 mg/g for the rCB-HNO3 and 54.80 mg/g for the rCB-T-HCl-HNO3