| Attapulgite clay,as a rare earth material,has a good application prospect in catalysis,adsorption,additives and other fields due to its special structure.As the country with the largest attapulgite reserves in the world,China has unique advantages in natural resources.However,although the output of attapulgite in China is high,its quality is poor and its application value is low.How to apply attapulgite with high value has become a challenging goal.Organic wastewater pollutes the environment,threatens human health and affects the sustainable development of ecology.Fenton reagent is called an efficient,simple and economical organic wastewater treatment technology.This method uses Fe2+as catalyst and hydrogen peroxide(H2O2)as oxidant.Although Fenton process has been widely studied and performs well in organic wastewater treatment,it still has some disadvantages,such as high operating cost,large amount of iron mud formation,etc.After analysis and testing,the iron content of attapulgite clay in Gansu Province is relatively high.Based on the characteristics of attapulgite in Gansu province,a new Fenton reagent,attapulgite/H2O2,was constructed by combining attapulgite with H2O2,and its degradation of phenol wastewater was studied.Attapulgite used in the experiment does not need any purification treatment,which can further save the cost of treating organic wastewater.Meanwhile,Attapulgite clay samples were characterized by detailed physicochemical properties,the mechanism of degradation of phenol wastewater by Attapulgite was speculated,and the role of Fe element in phenol degradation reaction was discussed.In addition,in order to solve the problem of high-value application of attapulgite,the purity and chromaticity of attapulgite need to meet certain requirements,so that it can be applied in some fields.In this paper,the purification and whitening of attapulgite samples from Gansu Province were studied,several influencing factors in the process of purification and whitening were investigated,and the purification and whitening effects of attapulgite were characterized and studied.The main contents and results of this paper are as follows:1.Attapulgite clay raw powder from Gansu Province is adopted and directly added without pretreatment Attapulgite/H2O2,a Fenton reagent,was formed in hydrogen oxide,and its phenol degradation performance was studied.Under the optimal conditions,the degradation rate of phenol by attapulgite clay reached 94%under the following conditions:attapulgite clay content 0.5 g/L,H2O2 concentration 30 mmol/L,initial pH value 3,reaction temperature 20 C.In addition,the degradation rate of phenol can be maintained above 70%in a relatively wide pH range(pH=1-9).The composition,structure and morphology of attapulgite clay were characterized and studied.Through Mossbauer spectrum analysis,the composition and valence of Fe in attapulgite clay were simulated,and the mechanism of phenol degradation by Fenton reagent was discussed.Finally,the phenol degradation performance of attapulgite clay raw powder,acidified attapulgite and purified attapulgite were compared,and the role of Fe element in phenol degradation reaction by Fenton reagent was discussed.2.Attapulgite was purified and whitened in this paper.The effects of mixing method,dispersant type and dosage,centrifugal rate and other factors on purification of attapulgite were investigated.The research shows that 1 mol/L hydrochloric acid is used to dissolve acid-soluble impurities and Fe elements in attapulgite,then 4%sodium hexametaphosphate is added into attapulgite at a soil-water ratio of 1:10 to fully mix in a colloid mill,ultrasonic treatment is carried out for 30 min,centrifugation is carried out at a low speed of 2000 r/min,and vacuum drying is carried out to obtain purer attapulgite.At the same time,XRD and SEM analysis were used to compare the structure and morphology of attapulgite before and after purification and whitening,and the purification and whitening effects were evaluated. |
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