Hydrogen Peroxide/Phosphoric Acid Modification of Hydrochars for Sulfamethoxazole and Carbamazepine Adsorption: The Role of Oxygen-Containing Functional Groups

Abstract

Emerging pollutants, such as sulfonamide antibiotics and pharmaceuticals, have been widely detected in water and soils, posing serious environmental and human health concerns. Thus, it is urgent and necessary to develop a technology for removing them. In this work, a hydrothermal carbonization method was used to prepare the hydrochars (HCs) by pine sawdust with different temperatures. To improve the physicochemical properties of HCs, phosphoric acid (H 3 PO 4 ) and hydrogen peroxide (H 2 O 2 ) were used to modify these HCs, and they were referred to as PHCs and HHCs, respectively. The adsorption of sulfamethoxazole (SMX) and carbamazepine (CBZ) by pristine and modified HCs was investigated systematically. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) results indicated that the H 2 O 2 /H 3 PO 4 modification led to the formation of a disordered carbon structure and abundant pores. X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FTIR) spectroscopy results suggested that carboxyl (-COOH) and hydroxyl (-OH) functional groups of HCs increased after modification, which is the main reason for the higher sorption of SMX and CBZ on H 3 PO 4 /H 2 O 2 -modified HCs when compared with pristine HCs. In addition, the positive correlation between −COOH/C=O and logK d of these two chemicals also suggested that oxygen-containing functional groups played a crucial role in the sorption of SMX and CBZ. The strong hydrophobic interaction and π−π interaction between CBZ and pristine/modified HCs resulted in its higher adsorption when compared with SMX. The results of this study provide a novel perspective on the investigation of adsorption mechanisms and environmental behaviors for organic contaminants by pristine and modified HCs.

A New Process for Efficient Recovery of Rhodium from Spent Carbonyl Rhodium Catalyst by Microreactor

“…The infrared spectroscopy analysis results of the ROPAC spent homogeneous catalysts are shown in Figure 7 , where Rh-1 and Rh-2 represent the infrared spectra of the ROPAC spent catalyst before and after oxidation treatment, respectively. By comparative analysis, it can be observed that the absorption peak at 3485 cm −1 corresponds to the O-H stretching vibration [ 37 ]. The significant increase and broadening of this absorption peak indicate the presence of -OH entering the oil phase during the reaction.…”

Sustainable hydrothermal carbon for advanced electrochemical energy storage

“…244 Furthermore, a large number of CC bonds can be broken and the refractory organic matter in the biomass structure can be removed by the strong oxidation reaction of H 2 O 2 , resulting in an increase in the content of C and aromaticity of hydrochar-based materials. 245…”

Quantitative Evaluation of the Effects of Salt Concentration and pH on the Self-Assembly of Kaolin Nanoplatelets

“…These contaminants will be transported through the strata, potentially polluting groundwater, surface water, and deep soil layers. , The microstructure of clay particles impacts the reactivity, adsorption capacity, and transport properties of the soil, which in turn affect the migration and diffusion of pollutants in the natural environment . Furthermore, pollutants will cause changes in the chemical properties of the pore water, and for clay soil, which is extremely sensitive to the hydration environment, the impact on the microstructure of clay is undoubtedly tremendous. − …”