Tuning role and mechanism of paint sludge for characteristics of sewage sludge carbon: Paint sludge as a new macro-pores forming agent.

For the first time, paint sludge waste (PS) was used as a pore forming agent in the preparation of sewage sludge derived carbon (SC). The tuning role and mechanism of PS for characteristics of SC were explored. It was found that a sludge carbon (SCPS-Zn) with rich macro-, meso- and micro- porous could be produced by one-step pyrolytic process of sludge in the presence of PS and ZnCl2. Its surface area could reach as high as 680.5m2g-1 as 88.4 times and 4.8 times of sludge carbon without addition of PS and ZnCl2 (SC) and only addition of ZnCl2 (SCZn), respectively. The macro- pores fabricated by PS provided much inner-space for ZnCl2 to generate meso- and micro- porous, leading to a hierarchical porous structure. SCPS-Zn showed a high adsorption capacity of 685.4mgg-1 for Chrysophenine, which is 1.3 and 1.7 times that of SCPS and SCZn respectively. The adsorption difference could be simply attributed to the fact that the great molecules were difficult to enter micro- pores of SCZn. It was also found that the difference was also dependent on orientation of Chrysophenine, which was related to pH value of solution.