p‐Nitrophenol Removal by Bauxite Ore Assisted Ozonation and its Catalytic Potential

Abstract

The catalytic ozonation process (COP) has attracted wide attention in the treatment of recalcitrant organic contaminants because of its high efficiency and easy operation. In this study, the bauxite ore (BO) was used as a heterogeneous catalyst to catalyze ozonation of p-nitrophenol in water. Calcined BO (CBO) assisted COP (CBO-COP) exhibited a higher degradation and mineralization performance for p-nitrophenol in comparison with raw BO assisted COP and single ozonation process (SOP). The CBO-COP was dominated by hydroxyl radical mediated oxidation on the CBO surface, following a pseudo-first order kinetics with a reaction rate constant of 0.1944 min À 1 at 298.15 K and an activation energy of 6.476 kJ mol À 1. The reaction rate constants increased by about 76% at 298.15 K and 45% at 308.15 K and activation energy decreased by approximately 70% in CBO-COP compared to those in SOP. p-Nitrophenol in CBO-COP was first transformed into 4-nitrocatechol, pyrocatechol, hydroquinone, phenol pbenzoquinone, and o-benzoquinone, and then into benzoquinone, maleic acid, fumaric acid, acetic anhydride, acetic acid, formic acid, or directly mineralized to carbon dioxide and water. The results demonstrated the catalytic potential of BO for ozonation of recalcitrant organic contaminants considering low cost and earth-abundant reserves.

Scale-Up of Cluster Beam Deposition to the Gram Scale with the Matrix Assembly Cluster Source for Heterogeneous Catalysis (Catalytic Ozonation of Nitrophenol in Aqueous Solution)

“…The rate constants obtained here with the CBD catalysts prepared with the MACS (0.59 ± 0.02 min –1 for Au and 0.50 ± 0.01 min –1 for Ag) are higher than those reported with catalysts prepared by traditional chemical methods. For example, a calcined bauxite ore catalyst gave a pseudo-first-order rate constant of 0.194 min –1 , while the mesoporous α-MnO 2 catalyst gave a rate constant of 0.052 min –1 . This is similar to the value of 0.055 min –1 for a TiO 2 catalyst and 0.0043 min –1 for a titanium dioxide–magnetite composite .…”

The pH effect on the kinetics of 4-nitrophenol removal by CWPO with doped carbon black catalysts

“…Advanced oxidation processes (AOP) are particularly useful technologies to treat nondegradable compounds present in wastewaters in a wide range of initial concentrations (0.001-10 g•L −1 ) [7][8][9], difficult to remove by the conventional biological processes [10][11][12][13][14]. In this context, different AOPs have been studied, such as ozonation [15,16], photo-degradation [17,18] and electrochemical oxidation [19,20]. All these techniques allow to remove completely 4-NP after 0.25-6 h depending on conditions tested.…”

Clay, Zeolite and Oxide Minerals: Natural Catalytic Materials for the Ozonation of Organic Pollutants

“…Additionally, the identification of active sites is key to understanding the reaction mechanism. Phosphate, carbonate and bicarbonate have been employed to identify active sites, due to their high affinity towards Lewis acid sites and capacity to block them [ 76 ]. The activity and efficiency of the catalyst depend on the nature of the active sites, textural properties such as surface area, porosity and mechanical strength.…”

“…Regarding aluminum oxides of natural origin, only few studies are found in the literature. Among them, the studies of Qi et al [ 46 , 153 ] and Chen et al [ 76 ] using raw and modified bauxite (mineral mostly composed of alumina) will be described below.…”

“…Chen et al [ 76 ] used raw (BO) and calcined bauxite (CBO) ores in the catalytic ozonation of p-nitrophenol. The BO was washed, dried and ground.…”