Low Levels Of Methanol Research Articles

Uji daya mesin diesel dengan hot EGR menggunakan bahan bakar campuran biosolar, metanol kadar rendah, dan jatropha

Motorized vehicles that are very suitable for transportation and heavy equipment vehicles are diesel engines, because their high combustion efficiency, reliability, fuel flexibility, and low fuel consumption make diesel widely used in several countries. The purpose of this study was to determine the effect of using a mixture of biosolar fuels, low levels of methanol and jatropha on power in a diesel engine using the hot Exhaust Gas Recirculation (EGR) system. This study uses an experimental method, using a 4JB1 diesel engine, the percentage of biodiesel fuel mixture, low levels of methanol and jatropha, Low Purity Methanol has a moisture content of 24.88%. The ratio of biosolar mixture, methanol and jatropha used are D85LPM5J10, D80LPM10J10, D75LPM15J10, D75LPM5J20, D70LPM10J20, D65LPM15J20, D65LPM5J30, D60LPM10J30 and D55LPM15J30. EGR openings vary from 0%, 25%, 50%, 75% and 100%. The test is carried out at a constant speed of 2000 rpm and is given a load of 25%, 50%, 75% and 100%. This study uses a dynamite brand Land & Sea dynamite. The results of this study are the use of EGR resulted in increasing the value of brake power. The effect of the fuel mixture causes the value of brake power tends to fall compared to D100. When using D85LPM5J10, D80LPM10J10, D70LPM10J20 and D55LPM15J30 at low loads (25%) there is an increase in power by 12.03%, 7.50%, 5.01%, and 5.97%. Keywords: Power, Engine, Diesel, LPM, Jatropha, EGR.

Influence of methanol when used as a water-miscible carrier of pharmaceuticals in TiO2 photocatalytic degradation experiments

Research on the use of titanium dioxide (TiO2) for water treatment has expanded to include the degradation of pharmaceuticals and personal care products (PPCPs). PPCPs are typically introduced in aqueous solutions during TiO2 photocatalysis experiments using a water-miscible carrier solvent (e.g. methanol) to improve their solubility; however, carrier solvents may be detrimental to photocatalysis due to their scavenging effect. Although it is advisable to maintain the solvent at low concentrations, the influence of elevated concentrations of methanol or other solvents on photocatalysis has not been carefully explored. In this study, we examined the impacts of different methanol concentrations (0–0.2% v/v) on photocatalysis using P25 (commercial TiO2) and TiO2 nanomaterial synthesized via thermal and chemical oxidation (TCO). Scavenging of hydroxyl radicals by methanol was evident for both P25 and TCO but the effect was more prominent on TCO. Also, the photodegradation of some compounds using P25 were enhanced at low levels of methanol. Overall, this study highlights that trace amounts of methanol used as a carrier solvent can affect photocatalysis, especially in TiO2 nanomaterials with low reactivity. This should be considered carefully in future experiments so that the results are not biased by the introduction of carrier solvents.

Comment on “The environmental photolysis of perfluorooctanesulfonate, perfluorooctanoate, and related fluorochemicals”

Previous studies have shown that perfluoroalkyl carboxylicacids (PFCAs) and perfluoroalkane sulfonic acids (PFSAs) areextremely persistent in the environment with almost no naturaldegradation pathways (as summarized in risk assessment profilespublished by UNEP (2006) and ECHA (2013)), with the exceptionthat PFCAs may react with OH radicals (Hurley et al., 2004). In con-tradiction to this understanding, Taniyasu et al. (2013) proposedthat long-chain PFSA and PFCA homologues can undergo relativelyrapid photodegradation and form shorter-chain homologues undernatural conditions, based on findings from a combination of fieldand laboratory experiments.We have concerns about the strong conclusions drawn in thepaper by Taniyasu et al. given the absence of essential experimen-tal details (notably the UV light spectrum used in the laboratoryexperiments), internal inconsistencies in the experimental results,and the lack of a mechanism for photolytic degradation. We be-lieve that the observations in the Taniyasu et al. study can beattributed to experimental artifacts. Our three main points of con-cern are outlined below. For a better illustration of our concernsand to help the readers understand them, we compiled thereported percentage reduction of PFSA and PFCA homologues fromTaniyasu et al. after irradiation in the field and laboratoryexperiments in Table 1.[i] A plausible transformation mechanism is essential tounderstand the environmental relevance of their results, butis not provided (the authors stated, ‘‘Our study was not designedto address the mechanism of photolysis’’). When discussing theresults of the field experiments, the authors concluded, ‘‘We be-lieve that both direct and indirect photolysis have played a rolein the photolytic transformation of PFASs in this study’’. However,based on the following reasons, we believe that direct andindirect photolysis under natural light conditions should nothave occurred for (at least) perfluorooctane sulfonic acid(PFOS), perfluorooctanoic acid (PFOA) and perfluorodecanoic acid(PFDA).For the laboratory experiments, the authors did not report thelight conditions used, particularly the UV light spectrum and,therefore, a rational judgment on the environmental relevance ofthese experiments cannot be made. Taniyasu et al. observed signif-icant losses of PFOS, PFOA and PFDA in the experiments usingquartz glass tubes after a short time of irradiation (216 h), whereasno actual losses of these acids were observed in the experimentsusing Pyrex glass tubes after the same irradiation time (Table 1).Considering the lower wavelength cut-off for quartz glass(170 nm) compared to Pyrex glass (275 nm) (http://www2.chemistry.msu.edu/faculty/reusch/virttxtjml/photchem.htm), thephotolysis of PFOS, PFOA and PFDA in the laboratory experimentswith quartz glass was very likely induced by light with awavelength between 170 and 275 nm, which is clearly in the UV-C range. This implication is supported by a further analysis thattakes the settings of the field experiments into account.Regarding direct photolysis: The absorption spectrum of perflu-orooctanoic acid (PFOA) in water has been measured; PFOA showsstrong absorption from the deep UV-region to 220 nm and a weak,broad absorption from 220 to 270 nm (Hori et al., 2004), which isbelow the natural light spectrum at the surface of the Earth(>280 nm). The experimental conditions in the Taniyasu et al.study were different from those in the Hori et al. study, but wedo not believe that the addition of small amounts of methanol tothe water would significantly change the UV absorption spectrumof PFOA. Adding organic solvents such as methanol may change thepolarity of the solution and thus influence the spectra of the targetcompound (Kosower, 1958). However, the very low levels of meth-anol (<2%) in the solutions will have negligible influence on thepolarity of the solutions used in Taniyasu et al. (Kosower, 1958).In addition, it is unlikely that adding less than 2% of methanolhas any effect on the dissociation of PFOA (Sager et al., 1964).Therefore, the low levels of methanol (<2%) in the solutions are un-likely to have changed the absorption spectrum of PFOA comparedto the spectrum that was measured in pure water (Hori et al.,2004).Regarding indirect photolysis: The UV cut-off of methanol is inthe far UV region (<220 nm), i.e. methanol has no absorption oflight with wavelengths above 220 nm (Cheng et al., 2002). There-fore, it is very unlikely that methanol, under the conditions usedby Taniyasu et al. (wavelength above 280 nm, with reduced inten-sity of light from 280 to 315 nm due to Pyrex glass), absorbs andtransfers energy to PFCA and PFSA homologues.[ii] Reported reductions of long-chain PFCAs and PFSAs afterirradiation are not internally consistent between experiments(see Table 1). First, much lower degradation (or no degradationat all) of PFOS, PFOA and PFDA was observed in laboratory exper-iments using the same Pyrex tubes as in the field measurements,

The Combined Effects of pH and Percent Methanol on the HPLC Separation of Benzoic Acid and Phenol

The effect of varying mobile-phase pH and percent methanol on the reversed-phase HPLC separation of benzoic acid and phenol is investigated. Both analytes are of interest owing to their classification as moderate environmental and health hazards. Baseline separation of the analytes is observed in five of the nine mobile-phase compositions studied. At low levels of methanol, as pH increases, the elution order of the benzoic acid and phenol peaks reverses. A similar trend is observed at intermediate levels of methanol. At high levels of methanol, as pH increases, the two-component sample begins to resolve, but baseline resolution is never achieved. In general, as percent methanol increases, the retention time of both analytes decreases. This is independent of mobile-phase pH.

Effect of solvent removal technique on the matrix characteristics of polylactide/glycolide microspheres for peptide delivery

Porous salmon calcitonin (sCT)-loaded PLGA microspheres (size range 35–140μm) of varying matrix characteristics were prepared by an aqueous emulsification process using either a temperature gradient (Tmp) or dilution (Dil) of the continuous phase (CP). The Tmp technique resulted in microspheres with a hollow internal core and a porous wall. The core size and thickness of the porous wall were dependent on the temperature gradient used. A rapid ramp of temperature from 15 to 40°C resulted in a large core and a thin wall, while a gradual temperature rise resulted in a smaller core. The Dil technique produced microspheres with a uniform, honeycomb like pore structure without a core, pore size being dependent on the dilution volume used. The specific surface area was higher and bulk density lower for microspheres prepared by the Tmp technique while there was no significant difference in the peptide load (3.2–4.5%) between both techniques. A rapid removal of CH 2C1 2 was observed in case of the Tmp technique while the Dil technique facilitated a slower and gradual CH 2C1 2 removal. Residual CH 2Cl 2 was approximately < 10–20 ppm for microspheres prepared by the Tmp technique while the levels were 20–130 ppm for microspheres produced by the Dil technique. Higher retention of methanol (−15–50%) was observed in the droplet formation stage with the Tmp technique, subsequent removal of which affected the core size. In the Dil technique, very low levels of methanol (< 2%) were retained in the droplets soon after dispersion resulting in a uniform porous structure without core. Slower removal of methanol from the microspheres was partly responsible for the core formation.

Factors affecting competition between type I and type II methanotrophs in two-organism, continuous-flow reactors

Competition experiments were performed in a continuous-flow reactor using Methylosinus trichosporium OB3b, a type II methanotroph, and Methylomonas albus BG8, a type I methanotroph. The experiments were designed to establish conditions under which type II methanotrophs, which have significant cometabolic potential, prevail over type I strains. The primary determinants of species selection were dissolved methane, copper, and nitrate concentrations. Dissolved oxygen and methanol concentrations played secondary roles. M. trichosporium OB3b proved dominant under copper and nitratelimited conditions. The ratio of M. trichosporium to M. albus in the reactor increased ten-fold in less than 100 hours following the removal of copper from the reactor feed. Numbers of M. albus declined to levels that were below detection limits (<106/ml) under nitrogen-limited conditions. In the latter experiment, the competitive success of M. trichosporiumdepended on the maintenance of an ambient dissolved oxygen level below about 7.5 × 10(-5) M, or 30% of saturation with air. The ability of M. trichosporium to express soluble methane monooxygenase under copper limitation and nitrogenase under nitrate limitation was very significant. M. albus predominated under methane-limited conditions, especially when low levels of methanol were simultaneously added with methane to the reactor. The results imply that nitrogen limitation can be used to select for type II strains such as M. trichosporium OB3b.

Breath analysis by API/MS--human exposure to volatile organic solvents.

The expired breath of subjects, exposed for periods of ca. 90 min to atmospheres artificially contaminated with low levels of methanol, (ca. 100 ppm) toluene (ca. 50 ppm) or tetrachloroethylene, (ca. 50 ppm) was monitored during and after the exposure period using an atmospheric pressure ionization mass spectrometer, fitted with a direct breath analysis system. The retention of solvent by the subjects, estimated from steady state levels in the expired breath, averaged 82% of the inspired level for methanol, 83% for toluene and 87% for tetrachloroethylene. The elimination of unchanged solvent via respiration during the post exposure period followed first order kinetics with mean half life values of 24 min for methanol, 27 min for toluene and 79 min for tetrachloroethylene.