The objectives of the study are to use immobilized acclimated biomass and immobilized biomass-powdered activated carbon (PAC) as a novel approach in the bioregeneration of granular activated carbon (GAC) loaded with phenol and o-cresol, respectively, and to compare the efficiency and rate of the bioregeneration of the phenolic compound-loaded GAC using immobilized and suspended biomasses under varying GAC dosages. Bioregeneration of GAC loaded with phenol and o-cresol, respectively, was conducted in batch system using the sequential adsorption and biodegradation approach. The results showed that the bioregeneration efficiency of GAC loaded with phenol or o-cresol was basically the same irrespective of whether the immobilized or suspended biomass was used. Nonetheless, the duration for bioregeneration was longer under immobilized biomass. The beneficial effect of immobilized PAC-biomass for bioregeneration is the enhancement of the removal rate of the phenolic compounds via adsorption and the shortening of the bioregeneration duration.
In this work, the novel imprinted zeolite (IZ) was synthesized, and its properties and performance in terms of adsorption of p-Cresol, which represent the protein-bounded uremic toxins in aqueous phase under phosphate buffer saline, were studied and compared with the synthesized zeolite-Y (ZeoY-S) and commercial CBV 100 zeolite-Y (ZeoY-C). The ZeoY-S was synthesized from sodium aluminate, NaOH, H2O and SiO2 under aging for 24 h at room temperature and hydrothermal condition for 24 h at 100 °C, with an initial composition of 10SiO2:Al2O3:4Na2O:180H2O. The ZeoY-S has been modified by using the imprinting technology to produce the IZ via the use of p-Cresol as a template. The p-Cresol successfully imprinted on the zeolite-Y was proved through the multipoint Brunauer-Emmett-Teller (BET) and the performance of IZ that was compared to ZeoY-S and ZeoY-C. Based on the BET results, it proves that the pore size of IZ is in accordance with the target compound, which is p-Cresol at 0.79 nm. This modification was able to adsorb p-Cresol 2.5 and 3.5 times higher than ZeoY-S and ZeoY-C can, respectively. Langmuir and Freundlich adsorption isotherm models, together with the pseudo-first and -second order and intra-particle diffusion kinetics models, were used to investigate the adsorption behavior of p-Cresol on the zeolites. The IZ has 4.30 times greater competitive molecules than ZeoY-S and the properties of IZ were not influenced by the content of other phenolic group uremic toxins as competitive molecules. It can be concluded that the micropores of zeolite as adsorbent can be modified using the imprinting technology in order to increase its sensitivity and selectivity towards p-Cresol.
Oxidation of p-Cresol was investigated by using ozonation process. The aim of this research is to assess the effectiveness
of ozonation on oxidation of micropollutant such as p-Cresol. Ozonation performance was evaluated based on p-Cresol
concentration reduction and chemical oxidation demand (COD) reduction. It was found ozonation at pH11 achieved
the highest p-Cresol degradation, with 95.8% of p-Cresol reduced and 96.0% of COD reduced, for an initial 50 mgL-1
of p-Cresol. The degradation of p-Cresol could be expressed by second-order of kinetic model. The second-order rate
constant k increases as the initial pH increased, but decreases with the increasing of initial p-Cresol concentrations.
Besides, the absorption spectra of p-Cresol over ozonation time were analyzed by spectrophotometry. The evolution of
absorption spectra of p-Cresol degradation suggests that the oxidation of p-Cresol follows three stages mechanisms
with cycloaddition as the first step to produce aromatic intermediates followed by ring-opening reactions, degradation
of the intermediates, and subsequently achieved mineralization.
The title compound, C28H24N2O3, is a flexible Schiff base, having a dihedral angle of 59.53 (5)° between the mean planes of two phenyl rings bounded in the centre by a single O atom. The dihedral angles between the mean planes of the phenyl rings bonded to the central O atom and the mean planes of the terminal methyl-phenol rings are 31.47 (6) and 36.03 (5)°, respectively. The sp2-hybridized character of the azanylylidene groups is confirmed by their bond lengths and bond angles. In the crystal, mol-ecules are linked into centrosymmetric dimers by weak C-H⋯N inter-actions and connected into dimeric chains through weak C-H⋯O inter-actions. These chains are inter-connected into a two-dimensional network parallel to (1[Formula: see text]1) via weak C-H⋯π inter-actions.
3-Nitro-2-phenoxypyridine and 3-nitro-2-(4-methyl)phenoxypyridine were obtained when 2-chloro-3-nitropyridine was treated with phenol and p-cresol, respectively. Fluorescence studies were carried out in various solvents, in capped and uncapped conditions and for differing concentrations. Both 3-nitro-2-phenoxypyridine and 3-nitro-2-(4-methyl)phenoxypyridine were fluorescent compounds but 3-Nitro-2-(4-methyl)phenoxypyridine was more fluorescent than 3-nitro-2-phenoxypyridine in all the solvents used. The fluorescence intensity decreased with concentration and time.
The artificial neural network (ANN) modeling of m-cresol photodegradation was carried out for determination of the optimum and importance values of the effective variables to achieve the maximum efficiency. The photodegradation was carried out in the suspension of synthesized manganese doped ZnO nanoparticles under visible-light irradiation. The input considered effective variables of the photodegradation were irradiation time, pH, photocatalyst amount, and concentration of m-cresol while the efficiency was the only response as output. The performed experiments were designed into three data sets such as training, testing, and validation that were randomly splitted by the software's option. To obtain the optimum topologies, ANN was trained by quick propagation (QP), Incremental Back Propagation (IBP), Batch Back Propagation (BBP), and Levenberg-Marquardt (LM) algorithms for testing data set. The topologies were determined by the indicator of minimized root mean squared error (RMSE) for each algorithm. According to the indicator, the QP-4-8-1, IBP-4-15-1, BBP-4-6-1, and LM-4-10-1 were selected as the optimized topologies. Among the topologies, QP-4-8-1 has presented the minimum RMSE and absolute average deviation as well as maximum R-squared. Therefore, QP-4-8-1 was selected as final model for validation test and navigation of the process. The model was used for determination of the optimum values of the effective variables by a few three-dimensional plots. The optimum points of the variables were confirmed by further validated experiments. Moreover, the model predicted the relative importance of the variables which showed none of them was neglectable in this work.
Lignin extracted from oil palm fronds (OPF) underwent chemical modification by incorporating m-cresol into the lignin matrix. This study reports on the physicochemical properties and antioxidant activity of unmodified autohydrolyzed ethanol organosolv lignin (AH EOL) and the modified autohydrolyzed ethanol organosolv lignin (AHC EOL). The lignin samples were analyzed by FTIR, 1H and 13C NMR spectroscopy, 2D NMR: HSQC spectroscopy, CHN analysis, molecular weight distribution analysis; GPC and thermal analysis; DSC and TGA. The lignin modification has reduced the hydrophobicity of its complex structure by providing better quality lignin with smaller fragments and higher solubility rate in water (DAHCEOL: 42%>DAHEOL: 25%). It was revealed that the modification of lignin has improved their structural and antioxidant properties, thus venture their possible applications.
Photocatalytic degradation of p-cresol was carried out using ZnO under UV irradiation. The amount of photocatalyst, concentration of p-cresol and pH were studied as variables. The residual concentration and mineralization of p-cresol was monitored using a UV-visible spectrophotometer and total organic carbon (TOC) analyzer, respectively. The intermediates were detected by ultra high pressure liquid chromatography (UPLC). The highest photodegradation of p-cresol was observed at 2.5 g/L of ZnO and 100 ppm of p-cresol. P-cresol photocatalytic degradation was favorable in the pH range of 6-9. The detected intermediates were 4-hydroxy-benzaldehyde and 4-methyl-1,2-benzodiol. TOC studies show that 93% of total organic carbon was removed from solution during irradiation time. Reusability shows no significant reduction in photocatalytic performance in photodegrading p-cresol.
The effective removal of o-cresol is currently both an environmental and economic challenge. ZnO is not only an efficient photocatalyst but is also cost effective, as its photoabsorption can extend from the ultraviolet (UV) to the visible range thereby allowing the use of inexpensive visible light sources, such as sunlight. The principal objective of the present work is to investigate the visible light-driven removal of o-cresol from aqueous solution in the presence of 1.0 wt% Mn-doped ZnO. To measure the efficiency ofphotodegradation, the variables studied included the amount ofphotocatalyst, concentration of o-cresol, pH and irradiation time. The concentration ofo-cresol and residual organic carbon was monitored using a UV-visible spectrophotometer, ultra high-pressure liquid chromatography and a total organic carbon analyser. The optimum conditions under which the photodegradation of o-cresol was most favourable corresponded to 1.5 g/l ZnO, 35 ppm o-cresol and pH 9. The ZnO-1 wt% Mn photoprocess has demonstrated reusability for more than three times, which warrants its scale-up from laboratory- to in industrial-scale application.
Multiple contaminants including heavy metals and phenolic compounds are normally co-exist in wastewater, which caused the treatment process is rather complicated. Herein, the synergistic photoredox of Cr(VI) and p-cresol (pC) by innovative fibrous silica zirconia (FSZr) photocatalyst was reported. The high surface area of FSZr comprised of microspheres with a bicontinuous concentric lamella structure morphology consisted of silica, while its core consisted of ZrO2 structure. The rearrangement of FSZr framework increased the crystallinity, formed Si-O-Zr bonds and narrowed the band gap of ZrO2 for enhanced of photoredox of Cr(VI) and pC. Compared to the reaction, the photoredox efficiency of FSZr for removing Cr(VI) and pC in simultaneous system was found to be 96 % and 59 %, respectively which are higher than that in its single system owing to the efficient electron-hole charge separation. Phenolic compound with high degree of electron donating group gave beneficial effect to photoreduction of Cr(VI). Consequently, a proposed mechanism involving multi-photoredox pathway were proposed based on photoredox reaction and scavengers studies. FSZr sustained the simultaneous photoredox activities after five runs demonstrating its possibility to be use in the wastewater treatment of various pollutants.
Balamuthia mandrillaris and Naegleria fowleri are free-living amoebae that can cause life-threatening infections involving the central nervous system. The high mortality rates of these infections demonstrate an urgent need for novel treatment options against the amoebae. Considering that indole and thiazole compounds possess wide range of antiparasitic properties, novel bisindole and thiazole derivatives were synthesized and evaluated against the amoebae. The antiamoebic properties of four synthetic compounds i.e., two new bisindoles (2-Bromo-4-(di (1H-indol-3-yl)methyl)phenol (denoted as A1) and 2-Bromo-4-(di (1H-indol-3-yl)methyl)-6-methoxyphenol (A2)) and two known thiazole (4-(3-Nitrophenyl)-2-(2-(pyridin-3-ylmethylene)hydrazinyl)thiazole (A3) and 4-(Biphenyl-4-yl)-2-(2-(1-(pyridin-4-yl)ethylidene)hydrazinyl)thiazole (A4)) were evaluated against B. mandrillaris and N. fowleri. The ability of silver nanoparticle (AgNPs) conjugation to enrich antiamoebic activities of the compounds was also investigated. The synthetic heterocyclic compounds demonstrated up to 53% and 69% antiamoebic activities against B. mandrillaris and N. fowleri respectively, while resulting in up to 57% and 68% amoebistatic activities, respectively. Antiamoebic activities of the compounds were enhanced by up to 71% and 51% against B. mandrillaris and N. fowleri respectively, after conjugation with AgNPs. These compounds exhibited potential antiamoebic effects against B. mandrillaris and N. fowleri and conjugation of synthetic heterocyclic compounds with AgNPs enhanced their activity against the amoebae.
The co-existence of heavy metals and organic compounds including Cr(VI) and p-cresol (pC) in water environment becoming a challenge in the treatment processes. Herein, the synchronous photocatalytic reduction of Cr(VI) and oxidation of pC by silver oxide decorated on fibrous silica zirconia (AgO/FSZr) was reported. In this study, the catalysts were successfully developed using microemulsion and electrochemical techniques with various AgO loading (1, 5 and 10 wt%) and presented as 1, 5 and 10-AgO/FSZr. Catalytic activity was tested towards simultaneous photoredox of hexavalent chromium and p-cresol (Cr(VI)/pC) and was ranked as followed: 5-AgO/FSZr (96/78%) > 10-AgO/FSZr (87/61%) > 1-AgO/FSZr (47/24%) > FSZr (34/20%). The highest photocatalytic activity of 5-AgO/FSZr was established due to the strong interaction between FSZr and AgO and the lowest band gap energy, which resulted in less electron-hole recombination and further enhanced the photoredox activity. Cr(VI) ions act as a bridge between the positive charge of catalyst and cationic pC in pH 1 solution which can improve the photocatalytic reduction and oxidation of Cr(VI) and pC, respectively. The scavenger experiments further confirmed that the photogenerated electrons (e-) act as the main species for Cr(VI) to be reduced to Cr(III) while holes (h+) and hydroxyl radicals are domain for photooxidation of pC. The 5-AgO/FSZr was stable after 5 cycles of reaction, suggesting its potential for removal of Cr(VI) and pC simultaneously in the chemical industries.
Cloud point extraction (CPE) is a separation and preconcentration of non-ionic surfactant from one liquid phase to another. In this study, Sylgard 309 and three different types of additives for CPE, namely CPE-Sylgard, CPE-Sylgard-BMIMBr and CPE-Sylgard-GLDA, are investigated to extract methylphenol from water samples. The methylphenols are well separated by reversed-phase high-performance liquid chromatography (HPLC) with isocratic elution of acetonitrile : water; 60 : 40 (v/v) and detection at 260 nm. The optimized parameters for the effect of salt, surfactant, temperature, time of extraction, pH, interference study and the performance of different additives on methylphenol extraction are investigated. CPE-Sylgard-GLDA is chosen because it gives us a high peak and good peak area compared with CPE-Sylgard and CPE-Sylgard-BMIMBr. The recovery extractions of CPE-Sylgard-GLDA are obtained in the range of 80-99% as the percentage of relative standard deviation (RSD) is less than 10. The LOD and LOQ are 0.05 ppm and 0.18 ppm, respectively. The method developed for CPE-Sylgard-GLDA coupled with HPLC is feasible for the determination of methylphenol because it is simple, effective, cheap, and produces a high percentage of recovery.
The fabrication of an optical biosensor by using stacked films where 3-methyl-2-benzothiazolinone hydrazone (MBTH) was immobilized in a hybrid nafion/sol-gelsilicate film and laccase in a chitosan film for the detection of phenolic compounds wasdescribed. Quinone and/or phenoxy radical product from the enzymatic oxidation ofphenolic compounds was allowed to couple with MBTH to form a colored azo-dye productfor spectrophometric detection. The biosensor demonstrated a linear response to catecholconcentration range of 0.5-8.0 mM with detection limit of 0.33 mM and response time of10 min. The reproducibility of the fabricated biosensor was good with RSD value of 5.3 %(n = 8) and stable for at least 2 months. The use of the hybrid materials of nafion/sol-gelsilicate to immobilize laccase has altered the selectivity of the enzyme to various phenoliccompounds such as catechol, guaicol, o-cresol and m-cresol when compared to the non-immobilized enzyme. When immobilized in this hybrid film, the biosensor response onlyto catechol and not other phenolic compounds investigated. Immobilization in this hybridmaterial has enable the biosensor to be more selective to catechol compared with the non-immobilized enzyme. This shows that by a careful selection of different immobilizationmatrices, the selectivity of an enzyme can be modified to yield a biosensor with goodselectivity towards certain targeted analytes.
REVIEW QUESTION/OBJECTIVE: This review aims to determine the best available evidence related to the effectiveness of amylmetacresol and 2,4-dichlorobenzyl alcohol throat lozenges in patients with acute sore throat due to upper respiratory tract infection (URTI). The objective is to examine the analgesic properties of amylmetacresol and 2,4-dichlorobenzyl alcohol (AMC/DCBA) throat lozenge comparing with placebo for the relief of pain in patients with acute sore throat due to URTIs.The review question is:More specifically, the objectives are to.
The development of an optical biosensor based on immobilization of 3-methyl-2-benzothiazolinone hydrazone (MBTH) in hybrid nafion/sol-gel silicate film and tyrosinase in chitosan film for the detection of phenolic compounds has been described. Tyrosinase was immobilized in chitosan film deposited on the hybrid nafion/sol-gel silicate film containing MBTH. The enzymatic oxidation product of phenolic compounds were stabilized through formation of adduct with MBTH to produce a maroon color adduct. The color intensity of adduct was found to increase proportionally with the increase of the substrate concentrations after 5min exposure. The linearity of the biosensor towards phenol, catechol and m-cresol were in the respective concentration range of 0.5-7.0, 0.5-10.0 and 1.0-13.0mg/L with detection limit of 0.18, 0.23 and 0.43mg/L, respectively. The biosensor shows a good stability for at least 3 months.
The impacts of rubber variations (clonal, seasonal, and pre-treatment) were investigated to assess changes in the composition of volatile organic compounds (VOCs) emitted during rubber processing. VOC emissions from 14 different rubber types were evaluated by headspace micro-chamber (μ-TEC) extraction coupled with gas chromatography-mass spectrometry (GC-MS). Headspace extracted at 120 °C, which is equivalent to the drying temperature during rubber processing, revealed a significant number of odorants in terms of concentrations as well as odorant type. Volatile fatty acids (VFAs) such as acetic, propanoic, butanoic, pentanoic and hexanoic acids, were frequently detected at concentrations greater than their odour detection thresholds. Other odorous compounds including trimethylamine, p-cresol, butanone, indole, and phenol, were also detected. Emissions collected at ambient conditions represent odorants released during material storage (or maturation) and were dominated by benzene derivatives followed by ketones, aldehydes, esters, and acids. Emission composition during storage appeared to be governed by specific rubber properties such as protein and rubber moisture content. Seasonal variations revealed greater impacts on the concentration of VOCs for all studied clones, compared to pre-treatment variations, suggesting that the VOCs composition was seasonally dependent and may represents the 'potential' emissions from rubber as they are processed. A combination of sensorial and analytical measurements were used to produce odour wheels which may be used as tool to identify key malodours in onsite rubber processing. The linking of odours and odorants can facilitate communication between receptors (the public) and plant operators inorder to minimise odour impact and develop effective abatement and on-site management practices.
Oxyspiruriasis caused by the bird eyeworm, Oxyspirura mansoni, a thelaziid nematode, in three species of pheasants, 3 Chrysolophus pictus (golden pheasant), 7 Lophura nycthemera (silver pheasant) and 9 Phasianus colchicus (common pheasant) in Zoo Negara Malaysia are reported. Birds with the disease were treated with a solution of 0.5% iodine or 0.5% lysol. Antistress powder for 4 days in water and non-strep vitamin powder in water was also provided. Control measures included removal of the cockroach intermediate host, Pycnoscelus surinamensis (Surinam cockroach) from the vicinity of the birds. The golden pheasant is a new host for O. mansoni in peninsular Malaysia.
The stacked-film immobilization of 3-methyl-2-benzothiazolinone hydrazone (MBTH) in hybrid nafion/sol-gel silicate film and horseradish peroxidase (HRP) in chitosan, performed in order to allow the determination of phenolic compounds, was investigated via an optical method. The stacked films were deposited onto a microscope glass slide by a spin-coating technique. The quinone or free radical product formed by the enzymatic reactions of phenolic compounds interacts with MBTH to form azo-dye products, which can be measured spectrophotometrically at a wavelength of 500 nm. The color intensity of the product was found to increase in proportion to the phenolic concentration after 5 min of exposure. The response of the biosensor was linear over concentration ranges of 0.025-0.500, 0.010-0.070 and 0.050-0.300 mM for guaiacol, resorcinol and o-cresol, respectively, and gave detection limits of 0.010, 0.005 and 0.012 mM. The sensor exhibited good sensitivity and stability for at least two months.