This study aims to compare the performance of planted and unplanted constructed wetlands with gravel- and raw rice husk-based media for phenol and nitrogen removal. Four laboratory-scale horizontal subsurface-flow constructed wetland units, two of which planted with cattail (Typha latifolia) were operated outdoors. The units were operated at a nominal hydraulic retention time of 7 days and fed with domestic wastewater spiked with phenol concentration at 300 mg/L for 74 days and then at 500 mg/L for 198 days. The results show that planted wetland units performed better than the unplanted ones in the removal and mineralization of phenol. This was explained by the creation of more micro-aerobic zones in the root zone of the wetland plants which allow a faster rate of phenol biodegradation, and the phenol uptake by plants. The better performance of the rice husk-based planted wetland compared to that of the gravel-based planted wetland in phenol removal could be explained by the observation that more rhizomes were established in the rice husk-based wetland unit thus creating more micro-aerobic zones for phenol degradation. The role of rice husk as an adsorbent in phenol removal was considered not of importance.
The title aza-stilbene derivative, C14H13NO2 {systematic name: (E)-2-[(4-meth-oxy-benzyl-idene)amino]-phenol}, is a product of the condensation reaction between 4-meth-oxy-benzaldehyde and 2-amino-phenol. The mol-ecule adopts an E conformation with respect to the azomethine C=N bond and is almost planar, the dihedral angle between the two substituted benzene rings being 3.29 (4)°. The meth-oxy group is coplanar with the benzene ring to which it is attached, the Cmeth-yl-O-C-C torsion angle being -1.14 (12)°. There is an intra-molecular O-H⋯N hydrogen bond generating an S(5) ring motif. In the crystal, mol-ecules are linked via C-H⋯O hydrogen bonds, forming zigzag chains along [10-1]. The chains are linked via C-H⋯π inter-actions, forming a three-dimensional structure.
We report the draft genome sequence of Variovorax boronicumulans strain c24, which was isolated from a soil-inoculated chemostat culture amended with phenol as a sole carbon and energy source. The genome data will provide insights into phenol and other xenobiotic compound degradation mechanisms for bioremediation applications.
The adsorption of phenol, from aqueous solutions on activated carbon from waste tyres, was studied in a batch system at different initial concentrations (100-500mg/L) at 30°C for 48 hours. The activated carbon was prepared using the two-step physiochemical activation, with potassium hydroxide (KOH) at ratio KOH/char = 5. The carbonization process was done at 800°C for 1 hour with nitrogen flow rate 150ml/min, followed by the activation with the carbon dioxide flow rate 150ml/min at 800°C for 2 hours. The adsorption isotherms were determined by shaking 0.1g of activated carbon with 100ml phenol solutions. The initial and final concentrations of phenol in aqueous solution were analyzed using the UV-Visible Spectrophotometer (Shimadzu, UV-1601) at a wavelength of 270nm. Experimental isotherm data were analyzed using the Langmuir and Freundlich isotherm models.The equilibrium data for phenol adsorption could fit both isotherm models well with the R2 value of 0.9774 and 0.9895, respectively. The maximum adsorption capacity of the adsorbent obtained from the Langmuir model was up to 156.25 mg/g
Heat explosions are sometimes observed during the synthesis of phenol formaldehyde (PF) resin. This scenario can be attributed to the high latent heat that was released and not dissipated leading to the occurrence of a runaway reaction. The synthesis temperature and time played important roles in controlling the heat release, hence preventing the resin from hardening during the synthesis process. This study aims to assess the rheological and viscoelasticity behaviors of the PF resin prepared using paraformaldehyde. The prepared PF resin was designed for laminate applications. The rheological behavior of the PF resin was assessed based on the different molar ratios of phenol to paraformaldehyde (P:F) mixed in the formulation. The molar ratios were set at 1.00:1.25, 1.00:1.50 and 1.00:1.75 of P to F, respectively. The rheological study was focused at specific synthesis temperatures, namely 40, 60, 80 and 100 °C. The synthesis time was observed for 240 min; changes in physical structure and viscosity of the PF resins were noted. It was observed that the viscosity values of the PF resins prepared were directly proportional to the synthesis temperature and the formaldehyde content. The PF resin also exhibited shear thickening behavior for all samples synthesized at 60 °C and above. For all PF resin samples synthesized at 60 °C and above, their viscoelasticity results indicated that the storage modulus (G'), loss modulus(G″) and tan δ are proportionally dependent on both the synthesis temperature and the formaldehyde content. Heat explosions were observed during the synthesis of PF resin at the synthesis temperature of 100 °C. This scenario can lead to possible runaway reaction which can also compromise the safety of the operators.
The cost of chemicals prohibits many technically feasible enhanced oil recovery methods to be applied in oil fields. It is shown that by-products from oil palm processing can be a source of valuable chemicals. Analysis of the pyrolysis oil from oil palm shells, a by-product of the palm oil industry, reveals a complex mixture of mainly phenolic compounds, carboxylic acids, and aldehydes. The phenolic compounds were extracted from the pyrolysis oil by liquid-liquid extraction using alkali and an organic solvent and analyzed, indicating the presence of over 93% phenols and phenolic compounds. Simultaneous sulfonation and alkylation of the pyrolysis oil was carried out to produce surfactants for application in oil fields. The lowest measured surface tension and critical micelle concentration was 30.2 mNm(-1) and 0.22 wt%, respectively. Displacement tests showed that 7-14% of the original oil in place was recovered by using a combination of surfactants and xanthan (polymer) as additives.
This work evaluates the performance of ionic liquid in supported liquid membrane (SLM) for the removal of phenol from wastewater. Ionic liquids are organic salts entirely composed of organic cations and either organic or inorganic anions. Due to the fact that the vapor pressure of ionic liquid is not detectable and they are sparingly soluble in most conventional solvents, they can be applied in SLM as the organic phase. In this work, 1-n-alkyl-3-methylimidazolium salts, [C(n)MIM](+)[X](-) have been investigated so as to determine an optimal supported ionic liquid membrane. The effect of operational parameters such as pH, stirring speed and the concentration of stripping agent has been studied, and an evaluation of different membrane supports were also carried out. With a minimal amount of the ionic liquid 1-Butyl-3-methylimidazolium hydrogensulfate, 85% phenol removal could be achieved by using polytetrafluoroethylene hydrophobic membrane filter in the SLM.
Molecularly imprinted polymers (MIPs) were prepared by bulk polymerization in acetonitrile using 2,4-dinitrophenol, acrylamide, ethylene glycol dimethacrylate, and benzoyl peroxide, as the template, functional monomer, cross-linker, and initiator, respectively. The MIP membrane was prepared by hybridization of MIP particles with cellulose acetate (CA) and polystyrene (PS) after being ground and sieved. The prepared MIP membrane was characterized using Fourier transform infrared spectroscopy and scanning electron microscopy. The parameters studied for the removal of 2,4-dinitrophenol included the effect of pH, sorption kinetics, and the selectivity of the MIP membrane. Maximum sorption of 2,4-nitrophenol by the fabricated CA membrane with MIP (CA-MIP) and the PS membrane with MIP (PS-MIP) was observed at pH 7.0 and pH 5.0, respectively. The sorption of 2,4-dinitrophenol by CA-MIP and PS-MIP followed a pseudo-second-order kinetic model. For a selectivity study, 2,4-dichlorophenol, 3-chlorophenol, and phenol were selected as potential interferences. The sorption capability of CA-MIP and PS-MIP towards 2,4-dinitrophenol was observed to be higher than that of 2,4-dichlorophenol, 3-chlorophenol, or phenol.
A urea precursor was used for the first time to prepare mesoporous carbon nitride (MCN) by a thermal polymerization process with silica nanospheres as a hard template. Although the prepared MCN samples have similar structures and optical properties, it was revealed that the specific surface area, pore-size distribution, and morphology of the MCN samples depend on the initial mass ratio of urea to silica. Compared to the bulk carbon nitride (BCN) that only gave 20% phenol removal (6 h of irradiation), the activities can be enhanced up to 74% on MCN samples for photocatalytic removal of phenol under visible-light irradiation. The highest conversion was obtained on MCN with an initial mass ratio of urea to silica of 5, which has high surface area of 191 m(2) g(-1) and a nanoporous structure with uniform pore-size distribution of 7 nm. In addition to the high activity, the MCN sample also showed high photocatalytic stability.
A batch culture was enriched on phenol with trichloroethene-contaminated aquifer soil as an inoculum. Cupriavidus sp. strain P-10 was isolated from the culture using a diluted plating method. Here, we report the draft genome sequence and annotation of strain P-10, which provides insights into the metabolic processes of phenol degradation.
Pseudomonas sp. LAB-08 was isolated from a phenol-fed bioreactor constructed with contaminated aquifer soil as the inoculum. Strain LAB-08 utilized phenol as a sole carbon and energy source. Here, we report the genome sequence and annotation of Pseudomonas sp. LAB-08.
Papaya (Carica papaya L. cv. Hongkong) is an economically important fruit crop grown in Malaysia. During its ripening stages, (C. papaya L.) exhibits different physicochemical properties, antioxidant capacities, and sensory quality results. The objective of this study was to elucidate in detail the antioxidant capacity of C. papaya as determined by total phenol content (TPC), total flavonoid content (TFC), ferric reducing antioxidant power (FRAP),2,2-diphenyl-1-picrylhydrazyl (DPPH) and scavenging systemand (ABTS). The study also aimed to study physicochemical changes of papaya fruits based on measured pH, titratable acidity (TA), total soluble solids (TSS), moisture and fruit color at five different stages of ripening. The fruits were harvested at five different, stages RS1, RS2, RS3, RS4, and RS5 corresponding to 12, 14, 16, 18, and 20 weeks after anthesis, respectively. Significant differences were found at different stages of ripening. The pH of the fruit decreased significantly (P < 0.05), whereas TA, moisture, and TSS increased significantly (P < 0.05) during the ripening process. The redness (a*) and yellowness (b*) values of fruit color both increased significantly (P < 0.05), whereas
lightness (L*) varied. The total phenol content TPC, TFC, FRAP, DPPH and ABTS values increased significantly (P < 0.05) with the ripening process. Sensory evaluation based on the color, sweetness, sourness, flavor, and overall acceptance for the last three maturity stages was also performed. RS5 had a better score than RS3 or RS4. The results showed the important role of the ripening stage in increasing the antioxidant content of papaya fruits.
Environmental pollution is one of the major concerns in the 21st century; where billions of tonnes
of harmful chemicals are produced by industries such as petroleum, paints, food, rubber, and
plastic. Phenol and its derivatives infiltrate the ecosystems and have become one of the top major
pollutants worldwide. This review covers the major aspects of immobilization of phenoldegrading
bacteria as a method to improve phenol bioremediation. The use of various forms of
immobilization matrices is discussed along with the advantages and disadvantages of each of the
immobilization matrices especially when environmental usage is warranted. To be used as a
bioremediation tool, the immobilized system must not only be effective, but the matrices must be
non-toxic, non-polluting and if possible non-biodegradable. The mechanical, biological and
chemical stability of the system is paramount for long-term activity as well as price is an
important factor when the very large scale is a concern. The system must also be able to tolerate
high concentration of other toxicants especially heavy metals that form as co-contaminants, and
most immobilized systems are geared towards this last aspect as immobilization provides
protection from other contaminants.
Phenol Formaldehyde (PF) resin has been extensively used in the manufacturing industry as a binding agent, especially in the production of wood-based panels because of its ability to provide good moisture resistance, exterior strength and durability as well as excellent temperature stability. However, due to the use of limited petroleum-based phenol in its formulation, there is a strong interest in exploring renewable biomass material to partially substitute the petroleum-based phenol. In this study, the slow pyrolysis of biomass decomposition process was used to convert two types of biomass, namely, oil palm frond and Rhizophora hardwood, into bio-oil. The phenol-rich fraction of the bio-oil was separated and added into the formulation of PF resin to produce an environmentally-friendly type of PF resin, known as bio-oilphenol-formaldehyde (BPF) resin. This BPF resin was observed to have comparable viscosity, better alkalinity, improved non-volatile content and faster curing temperature than conventional PF resin. Moreover, the particleboard bonded with this BPF resin was observed to have just as excellent bonding strength as the one bonded using conventional PF resin. However, the BPF resin exhibited an increased level of free formaldehyde and less thermal stability than the conventional PF resin, probably due to the addition of the less reactive bio-oil.
The aim of the study was to develop response surface methodology (RSM) models for polymer loading, density, dimensional stability, strength and stiffness of compressed wood of sesenduk (Endospermum diadenum) treated with phenol formaldehyde (PF). Central composite design (CCD) using RSM with three processing parameters was studied in their specific ranges: PF concentration (PC) from 24-40%, pre-curing time (PCT), 3-9 h and compression ratio (CR), 70-90%. The experimental design was analysed and interpreted using the Design Expert Software (Stat Ease version 8) and the responses of 3d plots were built using the same software. Quadratic models in terms of PC, PCT and CR were developed for polymer loading, density, reduction in water absorption and modulus of rupture in static bending. Multiple linear equations were developed for anti-swelling efficiency and modulus of elasticity. The experimental values were in good agreement with predicted ones and the models were highly significant with correlation coefficients between 0.626 and 0.926. PC and CR had significant effects on the responses. The range of PCT used did not significantly affect the responses. It was also found that the improvement of properties ranged from moderately to highly correlated with the polymer loading in the compreg wood.
Different type of fibers which is EFB and KC were liquefied in phenol with the presence of sulphuric acid as a catalyst. The liquefied residue was characterized by using Fourier transform infrared (FTIR) to determine the functional groups presents in both residues, X-ray diffraction (XRD) to determine the degree of crystallinity in the residue, thermogravimetric analysis (TGA) to analyze the thermal properties of the residue and scanning electron microscope (SEM) to investigate the structure and morphology of the residue. Phenol-to-EFB/KC ratio shows great effect on the amount of residue in the liquefaction process. Peak appearance can be observed in the FTIR analysis at 810 and 750 cm-1 which is attributed to the para and meta benzene, respectively or to be specific its associated to the p-alkyl phenol and m-alkyl phenol. In the XRD analysis, CrI of lignocellulosic materials increased after liquefaction process. Liquefaction process caused chemical penetration across the grain of the fiber, thus the fiber bundles started to separate into individual fibers shown in the SEM micrograph and the weights lost curve for both liquefied EFB and KC experienced three region decompositions.
The valorization of lignin to replace phenol is significant in the production of phenolic resins. However, a great challenge is to produce lignin-based resin (LR) with a suitable viscosity and high substitution rate of lignin to phenol. In this study, LRs were produced using hardwood technical lignin derived from the pulping industry. Structural analysis of the LRs indicated that the unsubstituted para and ortho carbon atoms of the aromatic ring influenced the curing temperature and activation energy of the resins. The curing kinetics and thermal decomposition study implied that urea and methylene groups in cured LRs were significant factors that affected the thermal stability negatively. The prepared LRs showed desirable features if used as adhesives to make plywood. This is the first approach in which a substitution rate of up to 65 % is achieved for low-reactive-site hardwood lignin, which provides a solution to the challenge of the simultaneous realization of the high addition of lignin and the adaptive viscosity of resins.
Bio-novolac fibre made from phenol-formaldehyde derived oil palm empty fruit bunch (EFB) was produced using electrospinning method. The bio-novolac phenol-formaldehyde was prepared via liquefaction and resinification at two different molar ratios of formaldehyde to liquefied EFB (LEFB) (F:LEFB = 0.5:1 and 0.8:1). Electrospinning was applied to the bio-novolac phenol-formaldehyde (BPF) in order to form smooth and thin as-spun fibre. The BPF was electrospun at 15 kV and 15 cm distance between needle and collector at a flow rate of 0.5 mL/h. At lower molecular weight of BPF resin, beads formation was observed. The addition of poly(vinyl) butyral (Mw = 175,000 - 250,000) has improved the fibre formation with lesser beads hence produced more fibre. Polymer solution with higher molecular weight produced better quality fibre.
The purpose of the present research was to evaluate the phytochemical content and analgesic effect of Caralluma edulis
(Ce.Cr). Established methods were used for phytochemical analysis of plant. The anti-nociceptic activity of Ce.Cr was
scrutinized using acetic acid-induced writhings, tail immersion and hot plate methods. Ce.Cr was tested positive for the
presence of therapeutically active metabolites such as alkaloids, flavonoids, glycosides, phenol, tannins, terpenoids and
saponins. Ce.Cr at the dose of 10, 30 and 100 mg/kg inhibited acetic acid-induced abdominal writhes and increase the
latency time to thermal stimuli in both tail immersion and hot plate tests, similar to standard drug. These results showed
that the ethanolic extract of Caralluma edulis possesses anti-nociceptive property.
Burkholderia cenocepacia and Serratia marcescens are Gram-negative proteobacteria commonly found in the natural
environment and are also opportunistic pathogens that caused a number of human diseases. The fermentation culture of
Burkholderia cenocepacia yielded three compounds, 4-(2-hydroxyethoxy)-phenol (1), Maculosin (2) and methyl myristate
(3). Compound 2 was also isolated together with cyclo(L-Leu-L-Pro) (4) from Serratia marcescens. Compound 1 was
isolated from a natural source for the first time and the first isolation of compounds 2-4 was also reported from both
Burkholderia cenocepacia and Serratia marcescens.