Uncaria Gambir As Natural Corrosion Inhibitor For Mild Steel In Acidic Solution

Uncaria gambir, a native Southeast Asia herbal plant has been characterized and studied as a mild steel corrosion inhibitor in acidic media. It was revealed that ethyl acetate gambir extract gave the highest condensed tannin, phenol and flavonoid content compared with other solvent extracts. Quantification studies by means of HPLC have shown that more than 80 % (wt) of gambir extract consists mainly of catechin. The effect of both ethyl acetate gambir extract and (+)-catechin hydrate as corrosion inhibitors for mild steel in 1 M HCl solution was done using various techniques such as weight loss, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) measurements

Exploring the effect of cellulose nanowhiskers isolated from oil palm biomass on polylactic acid properties

In this work, polylactic acid (PLA) reinforced cellulose nanowhiskers (CNW) were prepared through solution casting technique. The CNW was first isolated from oil palm empty fruit bunch microcrystalline cellulose (OPEFB-MCC) by using 64% H2SO4 and was designated as CNW-S. The optical microscopy revealed that the large particle of OPEFB-MCC has been broken down by the hydrolysis treatment. The atomic force microscopy confirmed that the CNW-S obtained is in nanoscale dimension and appeared in individual rod-like character. The produced CNW-S was then incorporated with PLA at 1, 3, and 5 parts per hundred (phr) resins for the PLA-CNW-S nanocomposite production. The synthesized nanocomposites were then characterized by a mean of tensile properties and thermal stability. Interestingly to note that incorporating of 3 phr/CNW-S in PLA improved the tensile strength by 61%. Also, CNW-S loading showed a positive impact on the Young’s modulus of PLA. The elongation at break (Eb) of nanocomposites, however, decreased with the addition of CNW-S. Field emission scanning electron microscopy and transmission electron microscopy revealed that the CNW-S dispersed well in PLA at lower filler loading before it started to agglomerate at higher CNW-S loading (5 phr). The DSC analysis of the nanocomposites obtained showed that Tg,Tcc and Tm values of PLA were improved with CNW-S loading. The TGA analysis however, revealed that incopreated CNW-S in PLA effect the thermal stability (T10,T50 and Tmax) of nanocomposite, where it decrease linearly with CNW-S loading

Photoreactive carbon dots modified g-C3N4 for effective photooxidation of bisphenol-A under visible light irradiation

A series of carbon dots (CDs) modified g-C3N4 (xCDs/g-C3N4; x = 0.5, 1.0, and 1.5 mL CDs solution) was synthesized via the microwave-assisted hydrothermal synthesis method for the photooxidation of bisphenol-A (BPA) under visible light irradiation. The X-ray diffraction (XRD) analysis indicates that the CDs may have a turbostratic structure and the resulting photocatalysts have distorted crystal structure, as compared with pure g-C3N4. The high-resolution transmission electron microscope (HR-TEM) analysis revealed amorphous, mono-disperse, spherical CDs with an average particle size of 3.75 nm. The distribution of CDs within the matrix of g-C3N4 appear as small dark dot-like domains. The N2 adsorption-desorption analysis indicates that the nanocomposites are mesoporous with a density functional theory (DFT) estimate of the pore size distribution between 2–13 nm. The CDs quantum yield (QY) was determined to be 12% using the UV-vis spectral analysis, where the CDs/g-C3N4 has improved absorption in the visible region than g-C3N4. The higher BET surface area of CDs/g-C3N4 provided more adsorption sites and the ability to yield photogenerated e−/h+ pairs, which caused the 1.5 CDs/g-C3N4 to have better photocatalytic efficiency compared to the rest of the systems. The highest removal, 90%, was achieved at the following optimum conditions: BPA initial concentration = 20 mg L−1, catalyst dosage = 30 mg L−1, and pH = 10. The photooxidation process is mainly driven by photogenerated holes (h+) followed by •OH and O2•−. The synthesis of the 1.5 CDs/g-C3N4 system is simple and cost-effective, where this photocatalyst is highly stable and reusable versus other systems reported in the literature

Extraction, modification et caractérisation de lignine de frondes de palmier à huile pour la production d’inhibiteurs de corrosion dans solution d’acidique

Lignocellulosic biomass in Malaysia can be considered as one of the promising sources of renewable energy. It is mainly composed of cellulose, hemicellulose, and lignin and best-suited for energy and chemical applications due to its sufficient availability, inexpensive and is sustainable. In general, the production of lignocellulosic biomass in Malaysia was considered high and mainly derived from the palm oil industries (approximately 60 million tonnes of oil palm waste were generated in a year). The oil palm biomass waste could possibly be used as alternative resources for the production of paper and cardboard. However, massive amounts of lignin by-product could also be discarded in huge quantities (by the pulp and paper industry) due to lack of awareness on its potential. Having high content of diverse functional groups (phenolic and aliphatic –OH, carbonyls, carboxyls, etc.) and phenylpropanoid structure, lignin can lead to substitutes in industrial applications such as in corrosion inhibition of metals and alloys. Since the oil palm fronds (OPF) are one of the largest biomass waste contributors in Malaysia, it was therefore used as raw material in this study. In order to improve the lignin extractability and properties, the extraction was conducted in different ways (via direct delignification and/or combined pretreatment methods). Due to the high hydrophobicity of lignin, it limits the capability to act as efficient corrosion inhibitors. Hence, modifications of the OPF lignin structure were conducted in two ways; (1) by incorporating organic scavengers (2-naphthol and 1,8-dihydroxyanthraquinone) during autohydrolysis pretreatment before organosolv treatment (percentage yield of lignin: AHN EOL = 13.42±0.71 % and AHD EOL = 9.64±0.84 %) and (2) fractionation of lignin from direct delignification processes (Kraft, soda and organosolv) via ultrafiltration membrane technique (percentage yield of permeate lignin fractions: Kraft = 5.41±2.04 %; soda = 12.29±0.54 % and organosolv = 1.48±0.15 %). The physical and chemical properties of the modified lignins were evaluated by using Fourier Transform Infrared (FTIR) spectroscopy, nuclear magnetic resonance (NMR) spectroscopy, gel permeation chromatography (GPC), thermal analysis and high performance liquid chromatography (HPLC). Modified lignin fractions with higher phenolic –OH content but lower molecular weight, polydispersity as well as aliphatic –OH content resulted in higher values of antioxidant activities. The antioxidant activity seems be dependent on the increase of their free phenolic –OH and ortho-methoxyl content, through the stability of the radical formed and the ability to reduce Fe3+ ions to Fe2+ ions. Indeed, the improved physicochemical properties and antioxidant activity of modified lignin gave positive correlation with the mild steel corrosion inhibition action in 0.5 M HCl solution that were evaluated by electrochemical impedance spectroscopy (EIS), potentiodynamic polarization and weight loss measurements. The best percentage of inhibition efficiencies (IE: 81 – 90 %) were attained at the concentration of 500 ppm for all lignin inhibitors but decreased with the increase in temperature (303 – 333 K). Thermodynamic data indicated that the adsorption of the modified lignin onto the mild steel was spontaneous and the inhibitors were mainly physically adsorbed (physiosorption), supported by the activation energy of adsorption, Ea. The enhanced protective properties of the modified lignin will pave way for an alternative approach for the utilization of these natural waste materialsLa biomasse lignocellulosique en Malaisie peut être considérée comme l'une des sources d'énergie renouvelable prometteuse. Elle est principalement composée de cellulose, d'hémicellulose et de lignine et est adaptée pour des applications dans les domaines de l'énergie et de la chimie en raison de sa disponibilité suffisante, de son faible coût et de son caractère renouvelable. La production de biomasse lignocellulosique en Malaisie est considérée comme élevée et est issue en grande partie de l'industrie de l'huile de palme (environ 60 millions de tonnes de déchets d'huile de palme sont générés en un an). Les déchets de l’industrie de l'huile de palme pourraient être utilisés comme ressources alternatives pour la production de papier et de carton. Cependant, dans ce contexte, d'énormes quantités de lignine seraient rejetées (par l'industrie des pâtes et papier) en raison du manque de prise de conscience de son potentiel. Avec une teneur élevée en groupes fonctionnels divers (-OH phénoliques et aliphatiques, les carbonyles, les carboxyles, etc.), la lignine pourrait être utilisée en substitution de produits actuels dans des applications industrielles telles que l'inhibition de la corrosion des métaux et alliages. Les frondes de palmier à huile (OPF) étant l'un des plus gros contributeurs de déchets de biomasse en Malaisie, elles ont donc été utilisées comme matière première dans cette étude. Afin d'améliorer l'extractabilité de la lignine et ses propriétés, l'extraction a été effectuée de différentes façons (par délignification directe et / ou des méthodes de pré-traitement combiné). Cependant, la forte hydrophobicité de la lignine limite sa capacité à agir comme inhibiteur de corrosion efficace. Par conséquent, des modifications de la structure de la lignine OPF ont été effectuées de deux manières ; (1) en incorporant des piégeurs de recondensation de la lignine (2-naphtol et 1,8-dihydroxyanthraquinone) pendant le prétraitement par autohydrolyse avant le traitement organosolv (pourcentage de rendement de la lignine: AHN EOL = 13,42 ± 0,71% et AHD EOL = 9,64 ± 0,84%) et (2) le fractionnement de la lignine à partir de procédés de délignification directs (Kraft, à la soude et organosolv) par l'intermédiaire d'une technique d'ultrafiltration à membrane (rendement en pourcentage de fractions de lignine perméat: Kraft = 5,41 ± 2,04%; soude = 12,29 ± 0,54% et organosolv = 1,48 ± 0,15%). Les propriétés physiques et chimiques des lignines modifiées ont été évaluées en utilisant l'infrarouge à transformée de Fourier (FTIR), la résonance magnétique nucléaire (RMN), chromatographie par perméation de gel (GPC), l'analyse thermique et la Chromatographie liquide à haute performance (HPLC). Des fractions de lignine modifiée présentant des teneurs en OH phénoliques élevées, des poids moléculaires, polydispersité et contenus en OH aliphatiques faibles ont abouti à des valeurs plus élevées de l'activité antioxydante. L'activité antioxydante semble être dépendante de la teneur en OH phénolique et en ortho-méthoxyle, grâce à la stabilité du radical formé et la capacité de réduire les ions Fe3+ en Fe2+ ions. En effet, les propriétés physico-chimiques améliorées et une activité anti-oxydante de lignine modifiée a donné une corrélation positive avec l'inhibition de la corrosion de l'acier doux dans l'action solution de HCl 0,5 M qui a été évaluée par spectroscopie d'impédance électrochimique (SIE), de polarisation et de la perte de poids mesure potentiodynamique. La meilleure efficacité de pourcentage d'inhibition (ex: 81 à 90%) a été obtenu à la concentration de 500 ppm pour les inhibiteurs de la lignine, mais a diminué avec l'augmentation de la température (303 à 333 K). Les données thermodynamiques indiquent que l'adsorption de la lignine modifiée sur l'acier doux a été spontanée et que les inhibiteurs ont été principalement adsorbés physiquement (physisorption), ce résultat étant confirmé par l'énergie d'activation de l'adsorption, Ea. Les propriétés de protection renforcées de la lignine modifiée ouvriront la voie à une approche alternative pour l'utilisation de ces déchets naturel

Microcrystalline Cellulose-Blended Polyethersulfone Membranes for Enhanced Water Permeability and Humic Acid Removal

A novel polyethersulfone (PES)/microcrystalline cellulose (MCC) composite membrane for humic acid (HA) removal in water was fabricated using the phase inversion method by blending hydrophilic MCC with intrinsically hydrophobic PES in a lithium chloride/N,N-dimethylacetamide (LiCl/DMAc) co-solvent system. A rheological study indicated that the MCC-containing casting solutions exhibited a significant increase in viscosity, which directly influenced the composite membrane’s pore structure. Compared to the pristine PES membrane, the composite membranes have a larger surface pore size, elongated finger-like structure, and presence of sponge-like pores. The water contact angle and pure water flux of the composite membranes indicated an increase in hydrophilicity of the modified membranes. However, the permeability of the composite membranes started to decrease at 3 wt.% MCC and beyond. The natural organic matter removal experiments were performed using humic acid (HA) as the surface water pollutant. The hydrophobic HA rejection was significantly increased by the enhanced hydrophilic PES/MCC composite membrane via the hydrophobic–hydrophilic interaction and pore size exclusion. This study provides insight into the utilization of a low-cost and environmentally friendly additive to improve the hydrophilicity of PES membranes for efficient removal of HA in water

A study on the efficiency and effectiveness of the Malaysian anti-corruption commission with special reference to the international commission against corruption, Hong Kong / Muhammad Farhan Abd Ghani, Muhammad Aizat Mohd Zaid and Muhammad Hazwan Mohd Hussin

This research analyzed on the different features of the Malaysian Anti-Corruption Commission (MACC) with the Independent Commission Against Corruption (ICAC), Hong Kong. The differences were scrutinized to identify whether such differences of the features contribute to the efficiency and effectiveness of the MACC. Based on the differences identified, some recommendations were made with the intention to improve the efficiency and effectiveness of the MACC. The first chapter goes into the essences and structures of the research. In the second chapter, it focused on the different features of MACC and ICAC, Hong Kong which leads to their efficiency and effectiveness. The third chapter discussed on the special features of anti-corruption agency from other countries like Singapore, New South Wales and Finland. In the fourth chapter, the researchers outlined the findings of the research based on an interview and several emails from respondents. The research was concluded in the last chapter and some recommendations were made to propose on some improvements that can be imposed to the MACC to ensure its efficiency and its effectiveness in handling corruption in Malaysia

Unraveling the Effect of Kraft and Organosolv Processes on the Physicochemical Properties and Thermal Stability of Cellulose and Its Microcrystals Produced from Eucalyptus Globulus

Eucalyptus Globulus (EG) is a virtually untapped forest source that belongs to the hardwood family. The objective of this research is to understand the effect of two different isolation techniques, i.e., kraft and organosolv procedures, followed by either acidified sodium chlorite or alkaline hydrogen peroxide treatment on the properties of cellulose and microcrystalline cellulose (MCC) derived from EG. The MCC samples were successfully prepared from cellulose via acid hydrolysis. A comparative study was carried out on the extracted cellulose fibers and MCC samples through deep characterizations of lignocellulosic content, functional groups, crystallinity, thermal properties, and surface morphology. The detailed analyses exhibited that the prepared MCC samples using various approaches are similar to those of commercial MCC. It is revealed that the organosolv treatment followed by acidic bleaching provides the purest MCC with good thermal features, where the obtained cellulose has a glucose content of more than 97% and a degradation temperature of around 343 °C. The present work provides new insight into the effect of various extraction procedures on EG-MCC; these procedures are expected to be used in different industrial applications such as in biorefinery, dietary food, packaging, films, or reinforcement of polymer matrices

Antioxidant and anticorrosive properties of oil palm frond lignins extracted with different techniques

International audienceContext Oil palm (Elaeis guineensis Jacq.) fronds are produced as waste during the harvest of oil palm fruits. It mainly consists of cellulose, lignin, and hemicelluloses. Lignins like other polyphenols are potent free radical scavengers and are considered to be a valuable source of antioxidant phenolic compounds. AimsThe aim was to quantify the antioxidant properties of lignins extracted from oil palm biomass using Kraft, soda, and organosolv pulping. The potential of the extracted lignins as inhibitors of mild steel corrosion was also assessed. Methods Ground and dried 1–3-mm-mesh-size oil palm fronds were submitted to Kraft, soda, and organosolv pulping in rotary digesters. The extracted lignin was characterized and oxygen uptake was measured. Anticorrosion properties of extracted lignins were monitored via electrochemical measurements and surface analysis.Results Soda-extracted lignins displayed the highest antioxidant activities as compared to Kraft and ethanol organosolv lignins. The highest inhibition of corrosion of mild steel was reached in the presence of soda-extracted lignins.Conclusion Oil palm fronds are potential sources of lignins usable as green antioxidant for corrosion inhibition of mild steel

Condensed Tannins from Mangrove and Grape Pomace as Renewable Corrosion Inhibitors and Wood Adhesive

International audienc