Applied Fundamental Research On Recover Organic Substances From Raffinate By Resin Adsorption Method

With the rapid development of extraction technology in the field of separation applications,the extraction agent that is dissolved and entrained into the raffinate has become a focus of secondary pollution and process design.Due to the complex composition of the raffinate,in addition to the dissolved extractant that is not easily biodegradable,it also contains sulfides,nitrides,and high-concentration metal ions,and the morphological properties are greatly affected by the p H value in the water environment.Therefore,the separation process is proposed seriously test.It is particularly important to select a suitable recovery process without affecting the extraction of the target substance for the harmless treatment and resource utilization of the organic matter in the raffinate.As an important adsorption material in the field of adsorption and separation,resin is widely used in the treatment of oily wastewater due to its stable physical and chemical properties,high adsorption efficiency and outstanding regeneration ability.However,there is little research on the application of resin in the raffinate system,and there is a lack of extraction.Basic research on the adsorption of organic matter in the remaining liquid.In this paper,the resin adsorption process is applied to the recovery of organics in the raffinate,the effect of the resin adsorption technology on the recovery of organics in the raffinate is analyzed,and the feasibility of the technology in the actual raffinate treatment process is discussed.It is the recovery of organics in the raffinate.Provide a new process reference.This article mainly focuses on the research of the whole process separation and recovery of the organic matter in the raffinate produced by the metal extractant by the macroporous adsorption resin（organic matter in the vanadium raffinate,hereinafter referred to as OIVR）.The experiment completed the resin screening,pretreatment,adsorption/desorption conditions and the exploration of the adsorption mechanism through static adsorption,and carried out dynamic simulation experiments after obtaining relevant data.In order to achieve the goal of simulating the concentration of organic matter in water≤5mg/L,the adsorption column with the best diameter-to-height ratio and the space flow rate are selected,and the number of combined adsorption columns is selected according to the raffinate treatment capacity.The experiment uses commercially available resin to complete the entire process of recovering organics in the actual metal raffinate,which lays a theoretical foundation for the practical application of the process.The following conclusions are drawn through experiments:（1）WS6108 resin shows excellent adsorption performance among many macroporous adsorption resins.When the solid-to-liquid ratio is 24g/L,the adsorption environment temperature is 60℃,and the p H value is 11,the adsorption efficiency for OIVR is as high as96.7%.Among them,the metal ions are not lost during the adsorption process of the WS6108resin,but the adsorption efficiency of the resin is improved due to hydration,which becomes the outstanding advantage of the macroporous adsorption resin treatment raffinate system.The static desorption results show that methanol has a significant desorption effect on the loaded WS6108 resin,and the first desorption rate exceeds 96 under the best desorption conditions(v/v%=80%,p H=10,T=55℃,C_{Na Cl}=2000mg/L)%.In the 60 adsorption/desorption cycle experiments,the adsorption efficiency（96.2%）and desorption efficiency（99.5%）of WS6108resin for OIVR remained basically stable before 45 times,and the adsorption efficiency began to decrease around 45 times,and the adsorption efficiency of 60 times.The peak difference is about 3%.The SEM image shows that this may be related to the damage behavior of the resin.（2）Through adsorption isotherm and adsorption kinetic experiments,it is found that the saturated adsorption capacity of WS6108 resin and Langmuir equilibrium constant K_L increase with the increase of temperature at different temperatures,and the saturated adsorption capacity of the single layer can reach 138.89mg/g at 333K.It is in good agreement with the experimental results.From the results of thermodynamic function analysis,it is concluded that the adsorption process of WS6108 resin to OIVR is endothermic,non-spontaneous,and entropy increases,and the adsorption potential decreases with the increase in adsorption capacity.At the same time,the adsorption of WS6108 resin follows a pseudo-second-order kinetic model.The adsorption rate constants K₂ and Q_eincrease with the increase of temperature,indicating that heating can effectively improve the competitiveness of OIVR and obtain the adsorption sites of WS6108resin,thereby effectively improving the adsorption efficiency of the resin.The adsorption rate at 333K reached 0.745g/（mg·h）.The diffusion model shows that the adsorption process of WS6108 resin is jointly controlled by liquid film diffusion and pore diffusion,and according to the calculation results of activation energy,liquid film diffusion is the main speed control step.（3）Through dynamic simulation of the adsorption process,it is found that when the vanadium raffinate flows through an adsorption column with a diameter-to-height ratio of 1:10at a spatial flow rate of 1.5 BV/h,the penetration time is the longest and the resin utilization rate is the highest.According to the dynamic parameters calculated by Thomas model,the faster the flow rate,the earlier the penetration time.As the flow rate of the raffinate increases,the value of K_T（Thomas model coefficient）increases,and the saturated adsorption capacity decreases.At 1.5BV/h,the resin saturated adsorption capacity reaches 358.27mg/g.In the dynamic elution experiment,the desorption efficiency also decreases with the increase of the methanol flow rate,but the difference in desorption efficiency between 3BV/h and 1.5BV/h is only about 3%,and the elution peak difference is very small.For time considerations,3BV/h was selected,and the loading volume was 600m L as the dynamic desorption condition.Based on the above data,the same adsorption column is connected to form a multi-stage adsorption system,and the multi-stage adsorption penetration results show that when the organic concentration in the effluent reaches 5 mg/L,the second-stage feed volume reaches 1.45L,and the average adsorption capacity of the resin involved It is 124.18mg/g,the feed volume of the third stage is 4.55L,and the average adsorption capacity of the participating resin is 360mg/g,which is basically close to saturation.It can be concluded that the vanadium raffinate flows through a three-stage adsorption system composed of adsorption columns with a diameter-to-height ratio of 1:10 at a space velocity of 1.5 BV/h,and the resin utilization rate is the highest,and the raffinate processing capacity is as high as 4.55L.（4）The desorption solution（500m L,adsorbate concentration of 3.24g/L）accumulated for6 times of different batches of methanol recycling enrichment and desorption was recovered through fractional distillation to recover methanol and adsorbate.The quantitative results of each fraction showed that the recovery efficiency of methanol was as high as 94.6%,w/w=96.59%;the recovery efficiency of adsorbate was 94.42%,w/w=1.1%.From the chromatographic analysis results before and after the resin adsorption,it can be seen that the significant level（the highest signal value）of the raffinate before and after the adsorption is significantly different.Through adsorption,the types of organic matter in the raffinate dropped from 204 to 68,mainly aliphatic hydrocarbons,lipids and amine compounds.After fractionation,the macromolecular organic matter was decomposed,indicating that if the recovered adsorbate is reused,further investigation is needed.