Anchoring defective metal-free catalysts on montmorillonite nanosheets for tetracycline removal: synergetic adsorption-catalysis and mechanism insights

Abstract

One-step thermal polymerization approach was adopted to combine C3N5 with montmorillonite nanosheets (MMT Ns) to form xCN-MMT for the degradation of pollutants in water. Benefitting from the abundant hydroxyl groups...

Heterostructured Photocatalytic Fabric Composed of Ag3PO4 Nanoparticle-Decorated NH2-MIL-88B (Co/Fe) Crystalline Wires for Rhodamine B Adsorption and Degradation

“…The RhB removal by the adsorption and photocatalytic degradation exhibited negligible difference between neutral (80.3%) and basic (79.5%) conditions. However, the performance decreased slightly to 75.2% under the acidic conditions, probably because the existence of H + in the solution hindered the interaction between the cationic RhB and the photocatalyst. , …”

“…In Figure S4 of the XRD analysis, as the Co/Fe molar ratio increased from 0 to 0.2, the peak area attributed to the (002) crystal plane of NH 2 -MIL-88B decreased, implying the deteriorated crystalline regularity. , The average bond length of Co–O (2.08 Å) is larger than that of Fe–O (1.72 Å); when a heterogeneous metal is incorporated in NH 2 -MIL-88B, crystalline regularity is disrupted to produce pore defects in their crystal structure, collapsing the micropores (<2 nm). , Table shows a significant increase in the pore diameter of MIL x @C and Ag/MIL x @C, as the Co/Fe molar ratio was 0–0.2, supporting the occurrence of pore defects. Eventually, the crystalline defects and pore collapse can be advantageous for adsorption of relatively large molecules like RhB …”

“…Moreover, •OH – generated by the redox reaction may further react to produce different types of radicals as shown in eqs – , which can alter redox capability and adversely influence the photocatalytic performance. − Hence, as a test of the practical applicability of Ag/MIL 0.2 @C in wastewater treatment, total RhB removal by the combined effect of adsorption and photocatalytic degradation was investigated in the presence of various anionic chemicals (Figure a). In this regard, anions such as Cl – , H 2 PO 4 – , HCO 3 – , and SO 4 2– were chosen for test, as those anions are mostly contained in tap water …”

“…In this regard, anions such as Cl − , H 2 PO 4 − , HCO 3 − , and SO 4 2− were chosen for test, as those anions are mostly contained in tap water. 50 Until 60 min test in the dark, the RhB total removal % occurred mostly by adsorption and the performance was consistent regardless of the presence of anions (Cl . Among those anions, Cl − adversely influenced the RhB degradation, probably because of the rapid reaction (eq 8) between Cl − and •OH − with a relatively high rate constant of 4.3 × 10 9 L mol −1 s −1 .…”

“…Eventually, the crystalline defects and pore collapse can be advantageous for adsorption of relatively large molecules like RhB. 50 To investigate the bond interactions and surface chemistry of bimetallic MIL x and the associated heterojunction, XPS analysis was performed (Figure 4). MIL 0 @C exhibited Fe 2p 3/2 and Fe 2p 1/2 at 711.7 and 725.3 eV, respectively, which can be deconvoluted into two peaks Fe 3+ (710.1 and 723.6 eV) and Fe 2+ (712.9 and 727.1 eV).…”