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Other Feedstocks—Coal, Oil Shale, and Biomass
Published in James G. Speight, Handbook of Petrochemical Processes, 2019
Naphthalene and several tar acids are the important products extracted from volatile oils from coal tar. It is necessary to first extract the phenolic compounds from the oils and then to process the phenol-depleted oils for naphthalene recovery. Tar acids are produced by extraction of the oils with aqueous caustic soda at a temperature sufficient to prevent naphthalene from crystallizing. The phenols react with the sodium hydroxide to give the corresponding sodium salts as an aqueous extract known variously as crude sodium phenate, sodium phenolate, sodium carbolate, or sodium cresylate. The extract is separated from the phenol-free oils which are then taken for naphthalene recovery.
Treatment of Coal Industry Effluents
Published in Mihir Kumar Purkait, Piyal Mondal, Chang-Tang Chang, Treatment of Industrial Effluents, 2019
Mihir Kumar Purkait, Piyal Mondal, Chang-Tang Chang
All the pollutants of the spent ammoniacal liquor affect the ecology of the waste-receiving water. During the process, phenol is considered to be the most hazardous pollutant. The other objectionable substances include thiocyanate, thiosulfate, cyanide, etc. In some plants, spent ammoniacal liquor is utilized for quenching of hot coke, this practice destroys the toxic matters like phenols in the liquor, but as this causes heavy corrosion in the quenching cars and in other quenching equipment, the method is not generally favored. Being a valuable chemical by-product, phenol may be recovered instead of destroying it. For the recovery of phenol by liquid extraction methods, several techniques have been developed. Most of these processes use benzene as a solvent to extract phenol from the crude ammoniacal liquor, before entering for ammonia stripping. Other solvents used include light oil, petroleum oil, etc. The extracted phenols from all absorption process can be recovered by washing with sodium hydroxide solution. Phenol reacts with a caustic solution to produce sodium phenolate. The crude phenol is then liberated from it using gases containing carbon dioxide. The phenols, thiocyanates, thiosulfates, and ammonia can be biologically oxidized using certain microorganisms such as bacteria and yeast. When optimum pH and temperature are maintained, sufficient nutrients are added, and the reactor is suitably seeded, the proper loading of this phenolic substrate to the reactor may result in a desirable reduction of the pollution load of the waste. Phenol concentrations of ~800 mg/L may be treated biologically. In all practical cases, the phenol concentration in the waste ammoniacal liquor is too high to be treated directly by biological means.
Decontamination of chemical warfare and industrial agents
Published in Michael L. Madigan, First Responders Handbook, 2017
Liquid personal decontaminants are common in some countries. Sodium phenolate or sodium cresolate in alcohol solution are used for individual decontamination of nerve agents. Chloramines in alcohol solution, possibly with additional substances, are commonly used against, for example, mustard agent. Instead of liquid individual decontaminants, it is possible to use an absorbent powder such as bentonite (“fuller’s earth”). In the United States, the wet method formerly used was replaced by a decontaminant powder based on a mixture of resins, which decompose CW agents, and an absorbent.
A Novel Hollow-Fiber Membrane Embedded Co-axial Microdevice for Simultaneous Extraction and Stripping
Published in Solvent Extraction and Ion Exchange, 2020
Zifei Yan, Chencan Du, Yuchao Chen, Guangsheng Luo
Operation mode one. As shown in Scheme 2, the feed was the dispersed phase, and the extractant was the continuous phase, and they could form a water-in-oil emulsion in the pre-dispersion channel. The squeezing-flow regime was realized when the two phases passed through the T-junction microchannel. In the hollow-fiber membrane-embedded channel, the water-in-oil emulsion was further led into the tube side of the hollow-fiber membrane, and the back-extractant was injected from the shell side. In this way, the solute that was initially dissolved in the feed would be enriched into the back-extractant in the single microdevice. The back-extractant in the shell side could be directly sampled, and the emulsion of the feed and extractant in the tube side was led to a small test tube for phase separation, which was accomplished instantaneously. After phase separation, we sucked out the aqueous phase at the bottom and added excess sodium hydroxide solution to convert the residuary phenol to sodium phenolate. Then, the UV-vis spectrophotometer (SHIMADZU, UV-2450) was used to analyze the concentration of sodium phenolate in the back-extractant and the feed, and the concentration in the extractant could be calculated by the material balance of phenol.
Extraction of phenolic pollutants from industrial wastewater using a bulk ionic liquid membrane technique
Published in Environmental Technology, 2022
Khalid Farhod Chasib, Anwer Jassim Mohsen, K. J Jisha, Ramesh L. Gardas
Before analysis the samples were diluted to guarantee that the samples absorbances can be measured within the UV–Vis Spectrophotometer detection range. With a solution of 0.5 M HCl, The samples of feed were diluted, where only existing molecular phenol which given an acidic environment. Further, with a solution of 0.5M NaOH the samples of stripping were diluted, where phenol was merely existing in the form of sodium phenolate (phenolate ions). For detection of molecular phenol in the samples of feed, absorbances of sample were measured at 270, and 288 nm for detection of ion of phenolate in the samples of stripping [32,48].