Synthesis of porous bentonite organoclay granule and its adsorption of tributyltin

摘要

We report a new method to synthesise porous organoclay granules which is suitable for high flow rate wastewater treatment applications. Granulation process consists of three steps: mixing natural clay powder, fine coal dust and corn starch into a homogeneous mixture; granulating in a rotating tilted pan granulator by spraying water mist; and heat treatment firstly at 190 degrees C for 30 min to solidify and then calcined at 550 degrees C for 4 h to create pores. These procedures produced very strong porous clay granules with a crushing strength of 8.41 N, the permeability of the granules was 1.56 x 10(6) mD and hydraulic conductivity of 1.5 cm/s. To further enhance the adsorption performance, the granules were later modified by surfactant hexadecyltrimethylammonium bromide (HDTMA) and tested for its adsorption capacity for removing toxic antifouling agent tributyltin (TBT) at high flow rate. It was found that cationic HDTMA modification enhanced the TBT adsorption capacity by 20%. This new granulation method allows the mass production of porous organo clay granules while the porous granular clay is also a good substrate for coating material such as nano sized zero-valent iron to further extent its application.