Resource Utilization From Rapeseed Meal Processing Wastewater

Rapeseed Meal Processing Wastewater (RMPW) contains a variety of naturalproducts, which include protein, polyphenol, phytic acid and so on. To realize thecomprehensive utilization of RMPW and gain high value-added products to improvethe overall economy of RMPW. The following studies in this topic were carried out.1. To improve the economic feasibility and environmental friendliness ofrapeseed meal processing and utilization, a process for protein recovery from rapeseedmeal processing wastewater (RMPW) was developed. Analyses of particle sizedistribution and differential scanning calorimetry revealed that the dissolved proteinin RMPW could be effectively precipitated with acid-induced denaturization, whilethe protein associated with the emulsified oil could be released by heat treatment inalkali condition. Based on these observations, the recovery process with combinationof heat treatment with alkaline and acid precipitation was established. According tothe single factor tests and orthogonal experiment on process parameters, the optimizedcondition for RMPW protein recovery is RMPW adjusted to pH10and incubated at70℃for10min followed by precipitation at pH2.5, the protein recovery rate andpurity were62.11%and65.48%, respectively.2. To achieve the recycling of residual protein and polyphenol in RMPW, athree sections of countercurrent adsorption-elution cycle process was developed. Eachsection of adsorption adsorb1hour at106mg/mL AB-8.The first elution was proceed20min with one-third volume95%ethanol elution of wastewater. The secondelution was proceed20min with one-third wasterwater volume50%ethanol, whichcontain0.15mol/L HCl. The AB-8resin was used for next adsorption after elution.The polyphenol recovery rate were40.14%under the above condition. The totalrecovery rate of acid precipition protein and adsorption protein was79.83%.3. To solve the recycling problem of RMPW and improve the economicfeasibility and environmental friendliness of rapeseed meal processing and utilizationfurther, A process of precipitation-acid soluble-ion exchange for phytic extraction andpurification was improved. The raw material was RMPW,which has been removedprotein and polyphenol. The optimized condition for phytic acid precipition is RMPWadjust to pH7with NaOH and contains0.1mol/L CaO, the phytic acid precipition rateis93.5%. The precipition was dissolved with two times wasterwater volume4% acetic acid and purified with0.36g/mL732cation ion exchange resin. The obtainphytic acid solution dealed with freeze drying, and getting the production of phyticacid.The purity and recovery rate of phytic acid are63.55%and59.53%,respectively.The traditional anion exchange process could be avoided by using this process.