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Solution pH is one of the primary factors affecting the efficiency of water decontamination. Although the influence of pH on oxidants activation, catalyst activity, and reactive oxygen species have been widely explored, there is still a scarcity of systemic studies on the changes in the oxidation behavior of organic pollutants at different pH levels. Herein, we report the influence laws of pH on the forms, reactivities, active sites, degradation pathways, and products toxicities of organic pollutants. Changes in pH cause the protonation or deprotonation of organic pollutants and further affect their forms and chemistry (e.g., electrostatic force, hydrophobicity, and oxidation potential). The oxidation potential of organic pollutants follows the order: protonated form > pristine form > deprotonated form. Moreover, protonation or deprotonation can modify the active sites and degradation pathways of organic pollutants, wherein deprotonation renders them more susceptible to electrophilic attack, while protonation reduces their activity against electrophilic and nucleophilic attacks. Additionally, pH adjustments can modify the degradation pathway and the toxicity of transformation products. Overall, pH changes can affect the oxidation fate of organic pollutants by altering their structure, which distinguishes it from the effect of pH on oxidants or oxidant activation processes. [Display omitted] • Solution pH alters the oxidation behavior of organic pollutants. • Deprotonation augments the reactivity of organic pollutants while protonation diminishes it. • Protonation and deprotonation modify the active sites and degradation pathways. • The toxicity of the transformation products can be controlled by adjusting the solution pH [ABSTRACT FROM AUTHOR]

[Display omitted] • mAg 3 PO 4 @g-C 3 N 4 /PDS/Vis enhance CBZ degradation rate by 3.6-fold. • 87.15 % mineralization of CBZ was achieved in 30 min via mAg 3 PO 4 @g-C 3 N 4 /PDS/Vis. • 1O 2 -dominated ring-opening is identified to be key for improved mineralization. • Multiple PhACs in the effluent are simultaneously degraded with high mineralization. The wide occurrence of pharmaceutically active contaminants (PhACs) in aquatic environments has received more and more concern owing to the associated high risks to ecosystems. Even worse, conventional wastewater treatment techniques fail to provide effective decontamination for these emerging contaminants. Herein, we designed and constructed mAg 3 PO 4 @g-C 3 N 4 heterojunction for a persulfate-assisted photocatalytic system (mAg 3 PO 4 @g-C 3 N 4 /PDS/Vis) for the rapid and effective degradation of PhACs. Superior mineralization of CBZ (87.15 %) was achieved within 30-minute treatment with mAg 3 PO 4 @g-C 3 N 4 /PDS/Vis, exhibiting 11-fold enhancement compared to mAg 3 PO 4 /Vis system. Integrating experimental investigations with theoretical calculations, singlet oxygen (1O 2) was identified as the key reactive species, while the 1O 2 -dominated ring-opening pathway contributed significantly to the high mineralization of CBZ. Moreover, mAg 3 PO 4 @g-C 3 N 4 /PDS/Vis showed robust degradation performance of multiple PhACs across various water matrices. Multiple PhACs could be simultaneously degraded with high mineralization efficiency in the wastewater effluent, demonstrating the promising application of mAg 3 PO 4 @g-C 3 N 4 /PDS/Vis for decontaminating emerging contaminants in wastewater treatment. [ABSTRACT FROM AUTHOR]

Oxygen vacancies (OVs)-rich α-Ni 0.2 Fe 1.8 O 3 with dual metal sites was synthesized by Ni2+ isomorphously substituted α-Fe 2 O 3 to activate peroxymonosulfate (PMS) for aceclofenac (ACF) degradation. A novel insight was proposed for the overlooked role of H 2 O in the surface-complexed process between PMS and unsaturated metal sites induced by OVs. The surface-bond SO 4 ∙- and ∙OH were demonstrated as the dominant reactive oxygen species (ROS). In situ ATR and Raman spectra revealed the reaction of HSO 5 - with the surface metal sites by replacing the surface-bonded -OH. The DFT study revealed the spontaneous formation of hydrolyzed -OH on OVs (∆G=−1.45 eV), which was further replaced by HSO 5 - to complex with metal sites (∆G=−3.58 eV). The O Ⅰ of the H-O Ⅰ -O Ⅱ -SO 3 - was more readily bonded with the Ni or Fe sites around OVs, causing the O-O cleavage for SO 4 ∙- generation. This study proposed a brand-new perspective for the interfacial behavior of PMS activation. [Display omitted] • The α-Ni 0.2 Fe 1.8 O 3 with rich oxygen vacancies can excellently activate PMS. • The surface-bond SO 4 ∙- and ∙OH played a major role in the degradation of ACF. • HSO 5 - was mainly bonded to metal sites by replacing surface -OH groups. • The interfacial mechanism for PMS activation by α-Ni 0.2 Fe 1.8 O 3 was proposed. • The degradation pathway of ACF by α-Ni 0.2 Fe 1.8 O 3 /PMS system was deduced. [ABSTRACT FROM AUTHOR]