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O-cresol is an important chemical raw material, o-toluidine this paper as raw material, by diazotization, hydrolysis reaction of o-cresol, and the resulting waste acid, waste water treatment process were studied. In the diazotization reaction, the reaction of o-toluidine and sulfuric acid, cooling, the temperature dropped to 0 ℃ and then slowly dripping Gaja nitrate solution. In the hydrolysis reaction, the use of steam distillation side edge hydrolysis Preparation of o-cresol. Optimum reaction conditions were as follows: sulfuric acid concentration of 30% in 0.8ml · min -1 was added dropwise at a feed rate of 35% sodium nitrite solution was below the liquid level for diazotization, diazo acceleration of liquid drops 20ml · min -1 , sulfuric acid concentration of 50% hydrolyzed, 86.2% yield of o-cresol, determined by HPLC, the product purity of 99.5%. N3520 macroporous resin adsorption treatment of wastewater is a better method of o-cresol, optimum operating conditions are: adsorption conditions: pH value = 2, temperature, room temperature; flow rate, 4BV · h -1 ; grant processing volume, 26BV; desorption conditions: temperature, 40 ℃; flow rate, 1.0BV · h -1 ; release agent, 5% NaOH-60% ethanol, the amount, 2BV. After treatment, the effluent colorless, o-cresol removal gt; 99%, the concentration lt; 0.5mg · L -1 , COD value of less than 300mg · L -1 , water quality and more stable, reaching phenolic wastewater discharge standards 0.5mg · L -1 or less. Pretreatment with activated carbon adsorption process of small scale waste acid, and its optimal process conditions are: adsorption temperature between 15 ℃ ~ 25 ℃; spent acid flow 3BV · h; batch volume 60BV. COD in waste acid pretreatment values ??less than 250 mg · L -1 , greater than 95% removal efficiency. The pretreated waste acid for bipolar membrane electrodialysis experiments show that by changing the processing time can effectively recover the sulfate ions in the salt chamber from the original sulfate ion content 4.04mol · L -1 down 0.26mol · L -1 less room sulfuric acid ion concentration increased to 4.59mol · L -1 . . The activated carbon pre-treatment, and then after electrodialysis, recycling sulfuric acid COD value less than or equal 10mg · L -1 , removal efficiency greater than 99.6%; cresol content of less than 0.5mg · L -1 , o-cresol removal efficiency greater than 99.98%. Compared with the traditional process, the process of production has improved significantly; and reduces the amount of acid. While a more simple method of wastewater has been treated to achieve the emission standards 0.5mg · L -1 the following; waste acid has also been processed.
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