Showing papers on "Phenol published in 2021"

Highly effective adsorption of synthetic phenol effluent by a novel activated carbon prepared from fruit wastes of the Ceiba speciosa forest species

Abstract: Fruit wastes of the Ceiba speciosa forest species were employed as raw material for preparing activated carbon towards removing phenol from water. Concave cavities spread over the entire material surface were observed from characterization results, resulting in a high surface area, 842 m2 g−1. Adsorption isotherm and kinetic studies were performed under the best conditions of pH (7) and adsorbent dosage (0.83 g L−1). An increase in temperature from 298 K to 328 K disfavored the phenol adsorption, decreasing from 156.7 to 145 mg g−1 for the best-fit model, Langmuir. The thermodynamic results indicated that the phenol adsorption was spontaneous, favorable, and exothermic. The phenol concentration decay shows that the equilibrium is reached at 120 min. The pore volume and surface diffusion model (PVSDM) was employed satisfactorily to describe the phenol decay behavior. The surface diffusion coefficient values were in the range of 10−9 cm2 s−1. The external and the internal mass transfer were the rate-controlling mechanisms. Therefore, the application of fruit wastes from Ceiba speciosa as raw material for preparing activated carbon proved very efficient towards removing phenol from an aqueous medium. The activated carbon is an alternative material to suppress water contamination due to phenol-derived species.

Phenolic compounds in plant oils: A review of composition, analytical methods, and effect on oxidative stability

Abstract: Background Phenolic compounds from different plant sources, like fruits, vegetables, cereals, and herbs, have been excessively studied and widely used in different industrial areas, including food, medicine, and pharmaceuticals. Recently, special attention has been paid to the phenolic compounds of plant oils that have recently been found to vastly affect the oxidative stability of these products. Scope and approach This paper reviews the contents and types of phenolic compounds in their initial forms in plant oils and methods of their determination. Also, their impact on the oxidative stability of oils is discussed. Key findings and conclusions The total free content of phenolic compounds and the phenol profile in plant oils are very diverse and depend on the oil source and production method. Generally, the main oily source of these compounds is rice bran and olive fruits. Their high amounts can also be found in rapeseed, flaxseed, grapeseed, and pumpkin oils. The main groups of phenolic compounds in oils are phenolic acids and flavonoids. Additionally, lignans, secoiridoids, and phenolic derivatives are identified in some oils. The two main methods for the determination of phenolic compounds in oils include the spectrophotometric and chromatographic ones. The general principles of these assays are often modified by various authors to adapt them to research conditions. Available literature data confirmed the strong antioxidative activity of some phenolic compounds found in oils. However, further studies are needed to better understand the mechanism of their protective action on oils, especially under natural storage.

Application of phenol-cresol-formaldehyde resin as an adhesion promoter for bitumen and asphalt concrete

Abstract: In this study, the phenol-cresol-formaldehyde (PhCR-F) resin was synthesised from the phenolic fraction of coal tar resin and formaldehyde through polycondensation. The physico-mechanical propertie...

Peroxydisulfate activation process on copper oxide: Cu(III) as the predominant selective intermediate oxidant for phenol and waterborne antibiotics removal

Abstract: In this study, activated peroxydisulfate (PDS) by micrometer copper oxide (CuO) particles effectively degraded phenol and several antibiotics in water. Cupryl ion (Cu(III)) was proposed for the first time to be the predominant reactive species accounting for contaminants degradation in the CuO/PDS oxidation system. Singlet oxygen was also heavily produced from the superoxide radical anion (•O2−) decomposition was found to be but slightly involved in the degradation since it was rapidly quenched by water. Transformation pathways of phenol and several antibiotics were elucidated. The proposed mechanism mainly involved the generation of •O2− resulting from an outer-sphere surface PDS complexation which prompted the reduction of Cu(II) to Cu(I). Cu(I) was oxidized in Cu(III) by PDS or H2O2 and was reduced to Cu(II) by a one-electron oxidation of contaminants so that the catalytic effect involved alternate oxidation and reduction of copper. As the degradation process did not rely on sulfate or hydroxyl radical, chloride and bicarbonate ions showed no effect on phenol degradation, while sulfate ions and humic acid slightly hindered phenol degradation probably due to their sorption on CuO. Interestingly, the copper leaching from CuO was significantly limited to

Synthesis of alginate-coated magnetic nanocatalyst containing high-performance integrated enzyme for phenol removal

Abstract: Effluent containing phenol is hazardous wastewater for the environment and human health. In the current work, synthesis and characterization of a new bi-enzymatic, magnetic-core nanocatalyst was investigated, and its performance as nanocatalyst for phenol removal from wastewater was examined. The obtained data suggested that the maximum combination of Peroxidases (POD) and Polyphenol Oxidase (PPO) enzymes (CPPE) stabilization can be achieved at T = 20 °C, pH value of 8, glutehydrie concentration of 1.6%, and enzyme to nanoparticles ratio of 1:200. Furthermore, it was found that the immobilized enzymes had higher stability than free enzyme against change in pH, temperature and even their durability. The Immobilized enzymes were used for phenol removal, and 98.1% separation was observed after 145 min when H2O2 to phenol ratio was 1.2, and in high concentrations of phenol (in the range of 2–10 mM) in the presence of CPPE. Finally, the stabilized enzymes were used 7 times in the phenol removal process, and the enzymes retained about 50% of their initial activity after 6 uses. It seems that the CPPE-alginate nanocatalyst could be used in hazardous wastewater treatment in particular for phenol removal.

Meso-porous activated carbon from lignite waste and its application in methylene Blue adsorption and coke plant effluent treatment

Abstract: Coke plant wastewater contains many toxic pollutants such as phenol, cyanide, and ammonia, etc., handling and disposal of which has a significant impact on the environment and human health. A novel adsorbent based on lignite extraction waste was prepared and its effect on the removal of simulated methylene blue, phenol and colour (ortho, para-benzo quinone) from real coking wastewater was investigated. Lignite waste (residue) after humic acid separation has a significant quantity of oxidized functional groups along with residual KOH, which makes it suitable for the preparation of activated carbon with high surface area. Since hydrothermal extraction breaks coal-mineral-pore aggregate, the separation efficiency of ash-bearing minerals improved, 11 % ash coal prepared from the residue with 81.6 % yield. Prepared activated carbon from low ash residue has a mesoporous surface (49.8 nm pore size), 0.554 cm3/g of total pore volume, and 980 m2/gram BET surface area. The adsorption kinetics followed pseudo-second order (R2 = 0.984) for methylene blue, pseudo-second-order (R2 = 0.978) for phenol, and pseudo-first-order (R2 = 0.935) for colour adsorption. Adsorption isotherm at equilibrium shows a maximum adsorption capacity of 120 mg/g for methylene blue, 20.49 mg/g for phenol and 588.23 PtCo/g for colour. The adsorption isotherm was in good agreement with Langmuir isotherm (R2 = 0.989−0.994) compared to Freundlich model (R2 = 0.924−0.982). The presence of negatively charged surface favours the uptake of cationic groups. Apart from phenol and colour, the adsorbent can remove total organic carbon (TOC) by 93.6 % and thiocyanide by 6.7 %. Adsorbent reutilization studies show that, the regenerated adsorbent by thermal treatment can be used for 3 cycles.

Efficient Ni-based catalysts for the hydrotreatment of lignin dimer model compounds to cycloalkanes/cycloalkanols

Abstract: The noble-metal catalytic cleavage of ether bonds in lignin to obtain aromatic chemicals has achieved great success, and the development of a low-cost efficient catalyst is crucial. Herein, NixLay/CNT was designed for the hydrogenolysis of benzyl phenyl ether (BPE), diphenyl ether (DPE) and 2-phenethyl phenyl ether (PPE) under a relatively mild condition. Owing to the synergistic effect of Ni with La, the Ni–La catalyst was especially active. Moreover, not only could the Ni–La catalyst fracture the C–O bond, but it could also transform aromatic rings to produce cycloalkanes. Physicochemical characterizations were carried out by means of XRD, TEM, H2-TPR, NH3-TPD, pyridine-IR and XPS analyses. Based on the optimal reaction condition (240 °C, 4 h, 2.0 MPa H2), various model compounds could also be effectively hydrotreated to produce corresponding products. A mechanistic study revealed that cyclohexanol and methylcyclohexane were major products for the transfer cleavage of BPE. Furthermore, it has been illustrated that aryl groups played a significant role in the hydrogenation of phenol from the competitive catalytic hydrogenation reaction of phenol. This study opened up the possibility of the valorization of lignin using a rare earth metal as the co-catalyst for the selective cleavage of lignin model compounds to value-added chemicals.