Heterogeneous catalytic degradation of methylparaben using persulfate activated by natural magnetite; optimization and modeling by response surface methodology

Abstract

BACKGROUND In this study, a naturally magnetic semiconductor mineral (NM‐SCM) was used as a highly active, easily separable and green catalyst to activate persulfate (SPS) for the degradation of methylparaben (MeP) in aqueous solution by a heterogeneous catalyst system (SPS/NM‐SCM). NM‐SCM properties were characterized using field emission scanning electron microscope (FESEM), Brunauer–Emmett–Teller (BET), X‐ray diffraction (XRD), energy‐dispersive X‐ray (EDX) and vibrating sample magnetometer (VSM) analyses. The effects of contributing factors such as solution pH, NM‐SCM loading, SPS dosage and initial MeP concentration on MeP degradation were analyzed using response surface methodology (RSM) and Box–Behnken design (BBD). RESULTS The RSM model obtained from the present study (R2 > 0.99) showed a suitable correlation between the predicted values and experimental results of MeP degradation. Under optimized conditions (pH 6.5, SPS 5 mmol L−1, NM‐SCM 0.3 g L−1 and MeP 10 µmol L−1), a removal efficiency of 99.5% and a mineralization degree of 37% were achieved. The removal efficiency of MeP was reduced in the presence of inorganic ions as follows: chloride > nitrate > carbonate > phosphate. After five successive catalyst reuses, the degradation efficiency was >90%, indicating the excellent potential reusability of NM‐SCM catalyst. CONCLUSION Owing to the generation of highly reactive oxidizing species (SO4•−) and easy separation of the catalyst, the integration of NM‐SCM and SPS has great potential for the degradation of MeP from water and wastewater matrices. © 2019 Society of Chemical Industry

Ionic Liquid-Microwave-Based Extraction of Biflavonoids from Selaginella sinensis

“…RSM is a multivariate nonlinear regression method, which is widely applied in the optimization of natural products extraction [33]. After investigation of single factor experiment, IL concentration (0.4, 0.6, 0.8 mmol/L), solid-liquid ratio (1:9, 1:11, 1:13 g/mL) and radiation temperature (40, 50, 60 °C) were chosen as main influential parameters and further optimized via Box-Behnken design of RSM using AME and HIN yields as index.…”

Polyaniline coated hematite sand supported on graphene oxide (HS@PANI‐GO) as a new magnetic material for advanced catalytic oxidation based on sulfate radicals: optimization using response surface methodology

“…33 The sulfate radicals are obtained from the activation of peroxymonosulfate (PMS) or from the activation of persulfate (PS), using heat, UV or catalytic pathways. 35,[37][38][39][40] In recent years, great importance has been attributed to the heterogeneous activation of PS by iron ions (Fe 2+ or Fe 3+ ) for the degradation of organic pollutants in aqueous media. 41 However, the problem of the regeneration of iron ions after reaction is always apparent which requires additional operations.…”

“…In addition, the high stability and the low cost of these radicals make this process interesting from an environmental and economical point of view . The sulfate radicals are obtained from the activation of peroxymonosulfate (PMS) or from the activation of persulfate (PS), using heat, UV or catalytic pathways …”

Solar light‐induced photocatalytic degradation of methylparaben by g‐C3N4 in different water matrices

“…A literature survey reveals that g-C 3 N 4 (either modified or not) performs extremely well when used as a photocatalyst for dyes and organic micropollutants degradation. [34][35][36][37][38][39] With regards to the degradation of parabens (especially MeP), so far, several AOPs, including photocatalysis, 40,41 activation of persulfate, [42][43][44] electrochemical, 45,46 and sonochemical 47,48 processes and ozone oxidation, 49,50 have been tested. Despite the use of several semiconductor materials for the solar light-induced photocatalytic degradation of MeP to date, to the best of the authors' knowledge, there are no research data related to the use of g-C 3 N 4 for the removal of MeP.…”