Thin film dosimeters based on Rose Bengal dyed poly(vinyl alcohol)

Dyed poly(vinyl alcohol) (PVA) films were prepared by casting the aqueous solutions of PVA incorporating Rose Bengal (RB) dye with or without chloral hydrate on a horizontal glass plate. Such films are useful as routine high-dose dosimeters. These flexible plastic film dosimeters are bleached when exposed to n -ray photons. The useful range of application of these films depends on the concentration of chloral hydrate. RB/PVA film without chloral hydrate is suitable for application in the range of absorbed doses 10-150 kGy. The maximum range of RB/PVA films containing chloral hydrate ranges from 5 to 20 kGy depending on, and inversely proportional to, chloral hydrate concentration in the film. The radiation-chemical yield (G-value) of films was calculated to be in the range from 0.272 to 10.3 µmol/J, where it increases with the increase of both RB and chloral hydrate concentration in the film. The effects of temperature and relative humidity during irradiation as well as pre- and post-irradiation storage, on the radiation response of films are studied. Although, the response of these films depends on relative humidity during irradiation, they are highly stable for long times before and after irradiation when stored in dark and they are not affected by temperature that ranged from 0°C to 45°C during irradiation.     

Removal of Basic Dye from Aqueous Solution using Cinnamomum camphora Sawdust: Kinetics,Isotherms, Thermodynamics,and Mass-Transfer Processes

Cinnamomum camphora sawdust (CCS) was employed as a cheap and effective biosorbent to remove basic dye from aqueous solutions. The biosorbent was characterized by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FT-IR). Adsorption experiments were carried out in a batch system as a function of initial pH, adsorbent dose and particle size, ionic strength, initial dye concentration, and reaction temperature. The selected basic dye (malachite green) adsorption onto CCS significantly depended on these factors. By comparative kinetic analysis, the rate of sorption was conformed with good correlation to pseudo-second-order kinetics. Equilibrium data were fitted well by Langmuir isotherm with the maximum adsorption capacity of 155.0 mg/g at the temperature of 318 K and pH 7.0 ± 0.1. Thermodynamic parameters proved that malachite green dye biosorption process was spontaneous and endothermic within the investigated temperature range. The mechanism of adsorption was also studied. It was found that the adsorption of malachite green onto CCS was mainly governed by film diffusion. The electrostatic attractions and ionic interactions between malachite green dye and CCS might be responsible for the adsorption process. The comparative investigation suggested that the sawdust could be considered as a potential adsorbent for malachite green dye removal from wastewater.     

水合氯醛结晶工艺研究

对水合氯醛结晶工艺进行了研究,经实验确定了水合氯醛结晶的最佳工艺条件,获得了符合“BP93”标准的水合氯醛产品,产率达85％左右,结晶时间约为3．5h。     

Fenton‐ and Fenton‐Like AOPs for Wastewater Treatment: From Laboratory‐To‐Plant‐Scale Application

Abstract

Fenton‐and Fenton‐like AOPs systems have been utilized for the oxidative degradation of some chlorinated pollutants such as chloral hydrate or 1,1,1‐trichloroethane, and for the treatment of real industrial wastewaters. Both ferrous sulfate (FeSO₄ · 7 H₂O) and Mohr's salt (NH₄)₂Fe(SO₄)₂. 6 H₂O have been used as Fe²⁺ ion sources. With Mohr's salt (MS) the Fenton‐and Fenton‐like reaction has been successfully carried out under acidic (pH 3) and neutral (pH 7) reaction conditions. The new Fenton‐like system utilizes zero‐valent iron (Fe^o) instead of ferrous sulfate has been applied for the 1,1,1‐trichloroethane and chloral hydrate degradation. Similarly, the application of catechol‐ and hydroquinone‐driven Fenton reaction for the degradation of chloral hydrate under acidic and neutral pH is a new Fenton‐like AOPs approach. The photo‐Fenton‐like reactions such as Fe³⁺/hν, Fe²⁺/H₂O₂/hν, and ferrioxalate system have been also studied for the degradation of chloral hydrate. As an irradiation source a daily light or sun light have been used. In comparison with photoreactor experiments the best system was observed to be Fe³⁺/hν. In some experiments the influence of standing time prolongation after Fenton reaction on the final degradation efficiency due to hydrolysis of intermediates such as phosgene (CCl₂?O) has also been studied. The Fenton reaction was successfully utilized for the treatment of real industrial wastewaters, in two cases even in plant‐scale applications.     

Synthesis of multiwalled carbon nanotubes supported manganese and cobalt zinc oxides nanoparticles for the photodegradation of malachite green

Multiwalled carbon nanotubes (MWNTs) supported and unsupported bimetallic zinc and manganese oxides nanoparticles (Zn–Mn NPs) were synthesized by wet chemical precipitation method. Zn–Mn and MWNTs/Zn–Mn oxides NPs were used as photocatalysts for the photodegradation of malachite green in aqueous medium under UV irradiation. The photodegradation study of malachite green was carried out by UV/vis spectrophotometer. The Mn–Zn and MWNTs/Mn–Zn oxides NPs degraded about 93% and 96% of dye, respectively, within 2 h of irradiation time. Effect of several parameters like time, pH, catalyst dosage and concentration of dye on the photocatalytic degradation was studied. The optimum conditions were obtained at pH 9 (93% dye degraded in 1.5 h), at 0.0435 g of catalyst (76.04% of dye degraded in 1 h), at 12.5 ppm dye concentration (88.41% dye degraded in 45 min). The activity of recovered catalyst was also examined.     

乳状液膜法处理三氯乙醛废水的研究

本工作是用乳状液膜法处理三氯乙醛废水的初步实验.实验系将氢氧化钠水溶液包以煤油作为液膜,处理含有50—200ppm的三氯乙醛水溶液.实验考察了影响三氯乙醛渗透的一些因素,在适当的条件下可以脱除95%以上的三氯乙醛.并计算了该液膜体系的总包传质系数,结果表明它趋向于一个恒定值.     

Transport of Acid Dye in Nylon Film

The results of both steady-state permeation and non-steady-state dyeing experiments over a wide range of dye concentrations for a system consisting of an acid dye (C.I. Acid Blue 182) and a nylon 6 film were analysed on the basis of surface diffusion with simultaneous multimodal adsorption. The concentration dependence of the diffusion coefficient of the dye in the nylon film can be explained by surface diffusion incorporating one Nernst-type and two Langmuir-type adsorption mechanisms except when high concentrations of dye are applied. The concentration dependence of the diffusion coefficient taken from the permeation experiments in the high concentration region is predicted by a surface diffusion mechanism in which two true adsorption equilibria of the Langmuir type are established throughout the nylon, whereas only a pseudo-equilibrium adsorption of the Nernst type is achieved.     

水合氯醛结晶工艺研究

通过实验对水合氯醛的结晶工艺进行了优化研究,获得最佳工艺条件为：萃取剂氯仿加入温度为50℃,氯仿加入量与三氯乙醛和水的混合液体积比为1：1,结晶时间为5～6h。按上述工艺条件生产的产品为无色透明结晶颗粒,质量达到英国药典BP93标准。萃取剂氯仿可循环使用,从而降低生产成本。     

Development of dieldrin,endosulfan, and hexachlorobenzene‐imprinted polymers for dye‐displacement array sensing

Due to the toxicity associated with the exposure to organochlorine pesticides, new materials capable of selectively capturing and detecting these compounds are highly desirable. In this study, imprinted polymers were prepared using three organochlorine pesticides—dieldrin (DE), endosulfan (EN), or hexachlorobenzene (HCB) as templates. The MIPs were polymerized via precipitation polymerization. The yields were over 90% with particle sizes ranging from 62 to 214 nm. Binding studies combined with GC‐ECD analysis showed that each template is more selective to its corresponding MIP compared with the other two structurally homologous templates. These results were consistent with those obtained using UV–vis where more bromocresol green (BCG) dye was released when higher template concentrations were introduced to the corresponding BCG‐impregnated MIPs. Since unique selectivity response pattern for each of the MIPs was obtained, this demonstrated that the MIPs were selective and can be potentially used in dye‐displacement array sensing. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44401.     

Experimental determination of methane hydrate dissociation curve up to 55 MPa by using a small amount of surfactant as hydrate promoter

Methane hydrate equilibrium has been studied upon continuous heating of the water-hydrate-gas system within the temperature range of 275-300 K. This temperature range corresponds to equilibrium pressures of 3.15-55 MPa. The hydrate formation/dissociation experiments were carried out in a high-pressure reactor under isochoric conditions and with no agitation. A small amount of surfactant (0.02 wt% sodium dodecyl sulfate, SDS) was added to water to promote hydrate formation. It was demonstrated that SDS did not have any influence on the gas hydrate equilibrium, but increased drastically both the hydrate formation rate and the amount of water converted into hydrate, when compared with the experiments without surfactant. To understand and clarify the influence of SDS on hydrate formation, macroscopic observations of hydrate growth were carried out using gas propane as hydrate former in a fully transparent reactor. We observed that 10^-3 wt% SDS (230 times less than the Critical Micellar Concentration of SDS) were sufficient to prevent hydrate particles from agglomerating and forming a rigid hydrate film at the liquid-gas interface. In the presence of SDS, hydrates grew mainly on the reactor walls as a porous structure, which sucked the solution due to capillary forces. Hydrates grew with a high rate until about 97 wt% of the water present in the reactor was transformed into hydrate.Our data on methane hydrate equilibrium both confirm already published literature data and complement them within the pressure range of 20-55 MPa.     

Halochromic poly (lactic acid) film for acid base sensor

A novel strategy to engineer biodegradable halochromic film based on poly (lactic acid) (PLA) for pH sensorial substances was presented. The effect of polyethylene glycol (PEG) compositions and dye amount on the efficiency of halochromic pH film was observed. The interactions between PLA, PEG, and dye was evidence by Fourier transform infrared. UV–VIS results indicated the sensitivity of the halochromic film through color changes. Mechanical performance was investigated by tensile testing to assess the potential of the halochromic film. It was found that the halochromic pH film has a clear color response from yellow to purple at pH 3–11 with a rapid response time within a minute. The results also revealed that varying content of PEG showed a significant effect on response time compared with varying dye compositions. PLA/PEG film and dye formed new interactions where PEG increased the free volume of PLA and made it possible for the PEG and the dye to diffuse and entrap between PLA chain. In term of the film strength, the addition of PEG and dye improved the flexibility of PLA film, which enables great potential in many applications such as medical, textile, and packaging.     

Decolorization of azo dye Orange II by ferrate(VI)-hypochlorite liquid mixture, potassium ferrate(VI) and potassium permanganate

Ferrate(VI)-hypochlorite liquid mixture was prepared using hypochlorite, an industrial by-product, via wet oxidation method. Its oxidizing ability was investigated by decolorizing azo dye Orange II in batch experiments, and compared with potassium ferrate(VI) and potassium permanganate. Effects of the oxidant concentration, dye concentration, initial pH of dye solutions and UV 254 nm irradiation were examined. The color removal by potassium permanganate, potassium ferrate(VI) and the ferrate(VI)-hypochlorite liquid mixture at 30 min reached 17.7%, 62.0% and 95.2%, respectively. The ferrate(VI)-hypochlorite liquid mixture maintained a high decolorization efficiency over a wide pH range from 3.0 to 11.0, indicating that the initial solution pH had little impact on its oxidizing power. However, the decolorization efficiency by potassium permanganate was proved to be highly pH dependent and the lowest efficiency was observed at neutral pH. UV 254 nm irradiation did not enhance the decolorization efficiencies significantly for both the ferrate(VI)-hypochlorite liquid mixture and potassium permanganate over a wide pH range.     

Characterization of Nafion solutions and films and observation of the casting process using basic dyes as optical probes

The absorption spectrum of methylene blue and crystal violet (CV) in ethanol–water in the presence of Nafion exhibited metachromasy, but a little or no formation of the large aggregates of the dye was observed. This indicates that the dye molecules are bound to the surface of the miceller particles of the polymer, but the ability of Nafion to induce the aggregation of the dye is weak. The absorption spectrum of malachite green (MG) and CV was measured in a cast film of Nafion at varying ambient humidity. The spectral change with humidity indicates that the decrease in the water content of the film causes the increase of H⁺-ion concentration in the hydrophilic cluster of Nafion and, hence, leads to the protonation of the dyes. The absorption spectrum of a Nafion solution containing MG or CV was recorded in the process of casting. The dyes changed to the protonated form right after evaporation of most solvent from the solution. This suggests that the phase inversion occurs in the casting process. © 1995 John Wiley & Sons, Inc.     

Surfactant effects on hydrate formation in an unstirred gas/liquid system: Amendments to the previous study using HFC-32 and sodium dodecyl sulfate

This paper reports a set of experimental data of clathrate-hydrate formation from HFC-32 (difluoromethane) gas in contact with an aqueous solution of sodium dodecyl sulfate (SDS). This supersedes the corresponding data that we previously reported in this journal [Watanabe et al., 2005. Surfactant effects on hydrate formation in an unstirred gas/liquid system: an experimental study using HFC-32 and sodium dodecyl sulfate. Chemical Engineering Science 60, 4846-4857] with the new data reported herein, because of a suspicion of hydrate plugging occurring in the gas-feed line of our experimental system used to obtain the previous data. The new data show much higher levels in both the hydrate formation rate and the final water-to-hydrate conversion ratio as compared to the previous data. Neither the hydrate formation rate nor the water-to-hydrate conversion ratio exhibited a significant change with the SDS concentration in the aqueous phase over the range from 1000 to 4000 ppm.     

A study of colored siloxane-based polyurethane ionomer

The reaction of dye with toluene diisocyanate and dimethyldichlorosilane in the presence of other additives to form a colored siloxane-based polyurethane (PU) ionomer has been proven to occur by infrared spectra. In aqueous solution, the number-average particle size for the colored siloxane-based PU ionomer was found to increase with an increase in the NCO-to-OH ratio, dye concentration, and dimethyldichlorosilane concentration, as a result of increased free volume of the ionomer molecules. It is worthy to note that the amount of air diffusing into the film cast from colored siloxane-based PU ionomer was found to increase with an increase in the concentration of dimethyldichlorosilane instead of raising the ratio of NCO to OH or the concentration of dye, as a result of the formation of more porosities. In addition, the tensile strength of this film will be strengthened by raising the NCO/OH ratio or the concentration of dimethyldichlorosilane, whereas the elongation, on the other hand, can be substantially increased with increasing the concentration of dye instead of increasing the concentration of dimethyldichlorosilane for use in the PU ionomer system. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 69: 2097–2105, 1998     

Studies on the Removal of Bromocresol Green from Water by Solvent Sublation

Abstract

Bromocresol green (BG) was removed from an aqueous solution by solvent sublation of bromocresol green–hexadecyl‐pyridiumchlorid (HPC) complex (sublate) into 2‐octanol. The effects of many parameters, such as the amount of surfactant, airflow rates, pH, NaCl, and ethanol on the solvent sublation were studied. Different temperatures of the solvent sublation were also investigated. A ratio of surfactant to dye (1.25:1) was the most effective for the removal, with over 99% BG removed from the aqueous solution within 5 min. The removal rate was somewhat enhanced by higher airflow rates and almost independent of the volume of the organic solvent floating on the top of the aqueous column. The effects of electrolytes (e.g. NaCl) and non‐hydrophobic organics (e.g. ethanol) reduce the removal efficiency of solvent sublation. This process followed first order kinetics. A characteristic parameter, apparent activation energy of attachment of the sublate to bubbles, was estimated at a value of 1.3 kJ/mol. Furthermore, the simulation of the mathematical and experimental data was made with good results.     

Solar photocatalytic decolorization of dyes in solution with TiO2 film

Application of TiO₂ film to solar photocatalysis of organic dyes, including Methylene Blue (MB) (λ_max, 660 nm), RR195 (λ_max, 540 nm) and RY145 (λ_max, 420 nm), was investigated. It was found that after 6-h solar irradiation, the extent of color degradation of dyes using solar photocatalytic system without TiO₂ film was quite limited. The color removal percentage for MB, RR195, and RY145 was found to be 23.3, −9.3, and −20.7%, respectively, resulting from competitions between the photosensitizing reaction and formation of colored intermediates during solar irradiation. However, as TiO₂ film was applied, the color degradation capability of solar photocatalytic system was significantly improved, in spite of the fact that only approximately 7% of solar irradiation belongs to the UV region. The color removal percentage for MB, RR195, and RY145 was up to 93.6%, 85.3%, and 71.1%, respectively, after 6-h irradiation. We believed that in such a solar photocatalytic system immobilized with TiO₂ film, both the maximum absorbance wavelength of the dye and the adsorbability of the dye on TiO₂ film played significant roles on the rate and efficiency of color removal of the dye solutions. Moreover, the possible reaction mechanism was proposed. The solar photocatalytic process with immobilized TiO₂ film was found to follow the pseudo-first order reaction kinetics. Color removal rate of MB was almost twice of that of RY145. Accordingly, the photocatalytic degradation process using solar light as an irradiation source, and immobilized TiO₂ as a photocatalyst, showed potential application for the decolorization of wastewater.     

Photocatalytic degradation of Rhodamine B dye under UV/solar light using ZnO nanopowder synthesized by solution combustion route

Nano-sized ZnO powder with crystallite size in the range 12 to 50 nm were prepared by solution combustion route. The product was characterized by powder X-ray diffraction (PXRD), scanning electron microscope (SEM) and Fourier transform infrared spectroscopy (FTIR). Photocatalytic degradation of rhodamine B (RB) dye was carried out with ZnO nanopowder. The effect of parameters such as the crystallite size, amount of catalyst, concentration of the dye, pH and irradiation on photocatalytic degradation of RB is studied. The results reveal that the maximum decolorization (more than 95%) of dye occurred with ZnO catalyst in 8 min of stirring at basic pH under solar light irradiation. It was also found that chemical oxygen demand (COD) reduction takes place at a faster rate under solar light as compared to that of UV light. The results suggest that, the ZnO solar photocatalytic irradiation is better than the calcined ZnO/solar and UV light irradiation.     

Inhibition of purified pig and human liver retinyl ester hydrolase by pharmacologic agents

Identification of inhibitors of retinyl ester hydrolase (RFH) would help to elucidate its role in vitamin A metabolism in vivo. By using standard incubation conditions, the effects of 215 drugs as potential inhibitors of purified pig and human liver REH when acting on micellar substrate retinyl palmitate were evaluated at 16.7, 167, and 1670 μM. Out of the compounds tested, 103 were inhibitors of the pig liver enzyme. The most potent compounds, in order of decreasing activity, were chloral hydrate, lovastatin, phytomenadione, alimemazine, physostigmine, thioridazine, phenoxybenzamine, probucol, cinnarizine, cyclandelate, amiodarone, flupenthixol, and naftidrofuryl; this order is roughly similar to that of their inhibition of human liver REH. Of the 10 tricyclic ring-containing drugs tested, alimemazine was the most potent enzyme inhibitor. The concentrations necessary for 50% enzyme inhibition ranged from <2.6 up to >540 μM. Moreover, inhibitory kinetic studies showed that at least two pharmaceutica's, chloral hydrate and amiodarone, are potent REH inhibitors at therapeutically achievable serum concentrations. First-pass metabolites were inactive as REH inhibitors compared to that of the parent compounds, in the cases of chloral hydrate, lovastatin, and cyclandelate.     

Notes on the dissolution rate of gas hydrates in undersaturated water

An elementary model for the dissolution of pure hydrate in undersaturated water is proposed that combines intrinsic decomposition within a desorption film and the subsequent diffusion of the released hydrate guest species into bulk water. Applying the proposed approach to recently published measurements of the decomposition rates of methane (CH₄) and carbon dioxide (CO₂) hydrates in deep seawater suggests that the concentration of the hydrate guest species at the interface between desorption film and diffusive boundary layer may be much lower than ambient solubility. Calculations, however, fail to account for the observed proportionality of decomposition rate with solubility for both CH₄ and CO₂ hydrates. This may indicate a limitation in the range of applicability of published formulas for intrinsic hydrate decomposition rates.