The Modification Of Attapulgite Clay And The Application In Swine Wastewater

Attapulgite clay is crystal hydrated magnesium aluminum silicate with a unique layer-chain structure. It has good adsorption performance in water treatment because of its larger surface area and cation-exchange capacity.When modified with BS-12 and CTMAB, the hydrophobicity of attapulgite increases, enhancing its adsorption to organic contaminant.Attapulgite clay compared to traditional materials such as activated carbon, with a small dosage, pH wide range, high efficiency, is an affordable wastewater treatment agent.With the development of livestock and poultry manure production has increased rapidly,tetracycline antibiotics have long been widely used in livestock and poultry breeding because of having the characteristics of broad-spectrum, high quality and low price,as treatment and prevention of animal diseases and to promote animal growth. The traditional method of wastewater treatment is difficult to meet the needs of this high organic and antibiotic wastewater treatment, led to farms of the surrounding soil, water and air pollution, severely restricted on the sustainable development of the breeding industry.Based on the purpose of developing high performance attapulgite adsorbent, prepared two new materials. Dodecane-betaine(BS-12) and cetyltrimethylammonium bromide(CTMAB) modified attapulgite was used as an adsorbent. An extensive study was performed on the mineral characteristics and modification mechanism of attapulgite in terms of scanning electron microscope(SEM),chemical composition(FT-IR spectroscopy), basal spacing(XRD), thermal properties(TG-DSC).The results show that the surfactants were grafted on the surface of attapulgite, whose crystal structure was unaffected. The adsorption of organic contaminants by attapulgite was enhanced significantly when modified with BS-12 and CTMAB. The optimal conditions for adsorbing organic contaminant with amphoteric and cationic attapulgite were obtained:modified ratio was 100%, dosage of adsorbent were 16 g·L-1.Meanwhile, when pH was 4(pH of attapulgite modified with CTMAB was 6), the COD removal efficiencies in swine effluent with amphoteric and cationic attapulgite reached 88% and 92%, corresponding to the adsorption capacity of 79 mg·g-1 and 82 mg·g-1, respectively. The adsorption could be described by pseudo-second-order kinetics(R2>0.998).The adsorption features of amphoteric and cationic attapulgite was well fitted with Freundlich isotherm model and Langmuirisotherm model, respectively.Adsorption capacity of 3 kinds of tetracycline antibiotics(tetracycline, oxytetracycline and chlorotetracycline) on CTMAB-ATP increases with the increase of pH; with the adsorbent concentration increasing, the adsorption capacity decrease; with the Ca2+concentrations increasing,the adsorption capacity present slowly decreasing trend. The adsorption of 3 kinds of tetracycline antibiotics(tetracycline, oxytetracycline and chlorotetracycline) on CTMAB-ATP could be described by pseudo-second-order kinetics(R2>0.998).Adsorption isotherms of antibiotics with CTMAB-ATP can be well described by Langmuir isotherm model. Organo-attapulgite clay applied to organic wastewater treatment.Therefore, good adsorbability and settleability of organo-attapulgite make it practical in swine effluent treatment.