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[Display omitted] • Porous carbonaceous material (CMs) were fabricated via various porogenic agents. • The increase in total pore volume of CMs facilitated the catalytic process. • Defect category in carbon skeleton induced by porogenic action was revealed. • Reactive complexes were the foremost active species for catalytic oxidation. • The inner-sphere interaction between CMs and peroxydisulfate was inferred. Porous carbonaceous materials (CMs) have been praised as superior candidates in activating persulfate for antibiotic wastewater decontamination. Whereas, as one of the frequently reported nonradical pathways, the formation mechanism of the reactive complexes and their correlation with physicochemical properties of CMs have not been comprehensively unveiled. Herein, a series of carbonaceous materials (CMs) with different specific surface area (SSA) and defect structures were fabricated by using KCl, MgCl 2 , KHCO 3 and K 2 C 2 O 4 as porogenic agents to activate peroxydisulfate (PDS) for sulfadiazine (SDZ) degradation. Results showed that the total pore volume of CMs exhibited a good linearity with degradation rate, attributing to the combined effect of SSA, defect degree and oxygen-containing functional groups according to multiple regression model. The reactive complexes (CM/PDS*) were proved as the foremost active species for SDZ oxidation via a suite of solid evidences. Compared with that after PS addition, the current direction was reversed after SDZ addition in i-t curves shedding light on the sharp enhanced potential of CM/PDS* and much low potential of SDZ. Furthermore, the inner-sphere CM/PDS* originating from the formation of new covalent bonds between CMs and PDS was inferred due to the poor dependence between electron-donating capacity and SDZ degradation result. The CM/PDS* with considerably higher potential can extract electron from SDZ based on the excellent positive relationship between electron-accepting capacity of CMs and SDZ degradation effect. This study advances the mechanistic comprehension of nonradical PDS activation, and provides a multiple regression model to predict degradation effects of carbon materials. [ABSTRACT FROM AUTHOR]

[Display omitted] • Porous carbonaceous material (PCM) was made via different pretreatment strategies. • PCM made via ball milling for 60 min possessed the optimal PDS activation ability. • The sulfadiazine degradation positively correlated to defective degree of PCM. • C O groups were the active sites for sulfadiazine degradation by PCM/PDS system. Metal-free porous carbonaceous materials (PCM) are compelling for peroxydisulfate (PDS) activation. However, pore-creating processes are multifarious and their influences on PDS activation performance for organic degradation have not been elucidated. Herein, several PCM were synthesized via different pretreatment strategies, including manual grinding (MG), impregnation (IP) and ball milling (BM), to probe their influence on PDS activation efficiency. Therein, the PCM fabricated via BM for 60 min (BM60) was superior to all other varieties. The quantitative structure–activity relationship (QSAR) unveiled that BM accelerated the vertical expansion of turbostratic domains on PCM. The rate constant (k obs) of sulfadiazine (SDZ) degradation in PCM/PDS system positively correlated to the defective degree over PCM and C O content, indicating that the abundant defective structures over PCM contributed to enhance the PDS activation capacity by exposing more C O active sites. The C O groups can efficiently donate electrons to S 2 O 8 2− inducing the breakage of peroxy bond because of the brilliant electron donating capacities of BM60, which resulted in the generation of radicals. Robust mechanism studies by multiple electrochemical methods and in situ Raman technology suggested metastable intermediates (BM60/PDS*) with a higher redox potential was the predominant oxidant which can extract electrons from SDZ via a one-electron-transfer regime, while radicals were the secondary oxidants. This finding for the first time explicitly illuminated the electron transfer direction in the nonradical pathways of PDS activation for organics degradation by PCM and deepened the fundamental understanding on the electron-transfer pathway. [ABSTRACT FROM AUTHOR]