Importance of inorganics in waste papers in regulating pore structures of resulting activated carbon for efficient removal of phenol and tetracycline.

Waste paper generation in China has been increasing significantly. Except cellulose, some paper products such as cardboard box (CB) and A4 paper (A4) also contained abundant inorganics, which might not be inert in activation. To understand potential involvement of inorganics in evolution of pores in AC, activation of papers of varied ash content (0.3 % for toilet paper (TP), 13.9 % for CB and 20.5 % for A4) with ZnCl2 or K2C2O4 was performed. The results indicated that abundant inorganics in CB or A4 suppressed inter-molecular condensation reactions in activation with ZnCl2, while intensified cracking reactions in activation with K2C2O4, diminishing yields of activated carbon (AC). Sufficient dehydration/condensation in activation of TP with ZnCl2 also formed AC of higher SBET. However, abundant inorganics in A4 or CB enhanced pore development via cracking in activation with K2C2O4. This further affected capability of the ACs for adsorption of phenol or tetracycline of distinct molecular sizes.