Fan Zhang,Chuting Yang,Yi Li,Min Chen,Sheng Hu,Haiming Cheng
P,P-bis (2-oxooxazolidin-3-yl)-N-(3-(triethoxysilyl)propyl)phosphinic amide (APTES-BOP)-modified SBA-15 (SBA-15-BOP) was prepared by a post-synthesis grafting method for the removal of anionic azo dyes from aqueous solutions. The properties of the prepared adsorbent were characterized by PXRD, FT-IR, SEM, TEM, nitrogen sorption, and elemental analysis. Adsorption equilibrium and adsorption kinetic studies demonstrated that the experimental data fitted well with the Langmuir isotherm model and pseudo-second-order model. According to Langmuir fitting, SBA-15-BOP showed high adsorption capacity for CR and RR2 dyes, with the maximum adsorption capacities of 518.1 mg g−1 and 253.8 mg g−1, respectively. The thermodynamic study indicated that the adsorption processes of CR and RR2 dyes on SBA-15-BOP were spontaneous and exothermal. The prepared SBA-15-BOP can be a promising adsorbent for the removal of anionic dyes from aqueous solutions.
Jinyu Wang,Xiangshun Li,Liming Wang,Xiaohong Qin,Yunhua Cui
The color of textiles plays a crucial role in meeting humans’ aesthetics needs and pleasure. Nanofiber has potential application prospects in textile and apparel due to its superior properties, such as the high specific surface area and porosity. Simultaneously, the coloring property has attracted widespread attention. However, the dyeing of polyacrylonitrile (PAN) nanofibers with reactive dyes remains a challenge due to the lack of reactive groups. Herein, an efficient strategy is proposed to successfully color electrospun PAN nanofibers with CI Reactive Red 2, enabled by introducing polyethyleneimine (PEI). Firstly, through entangling the molecular chain of PEI in solution, PAN is endowed with abundant cationic groups. Then, PAN/PEI nanofibers were obtained by electrospinning technology and further dyed using the reactive dye. More specifically, the different dyeing parameters, such as dyeing time, temperature, concentration and PEI concentration, were optimized. Compared to pure PAN nanofiber, PAN/PEI nanofiber achieved a higher dye uptake (96%) and better color fastness. This work offers an energy-saving and simple manner for improving the dyeing performance of PAN nanofibers using reactive dye.
In this study, a novel solid-phase redox mediator (RM) was manufactured via immobilizing anthraquinone-2-sulfonate (AQS) onto modified biochar (BC). The RM was used to enhance the anaerobic granular sludge (AGS) driven anaerobic biodegradation of azo dyes. Prepared at the optimal pyrolysis temperature of 550 ℃, the AQS modified BC550 exhibits a higher adsorption capacity of about 12.81% toward AQS compared to that of commercial granular activated carbon (GAC). X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy analyses showed that BC550-AQS contained more redox moieties (quinone and C = O) than GAC-AQS, indicating that the BC550 is suitable as a carrier of immobilized AQS. During the 36-h reaction, incubation of BC550-AQS as the solid-phase RM obviously enhanced the capacity of AGS (BC550-AQS + AGS), evidenced by the maximum percentage of Reactive Red 2 (RR2) decolorization (92.27%), which increased up by 80.55% and 14.48% compared to the controls (BC550-AQS, 17.95%) and (GAC-AQS + AGS, 78.61%). Besides, BC550-AQS exhibits good reusability and a higher RR2 decolorization rate (per AQS dosage) over 15 consecutive cycles. The mechanism of biodegradation pathway of RR2 initiated by BC550-AQS was studied using liquid chromatography-mass spectrometry and chemical computation. Density-functional theory calculations successfully predict that the RR2 biodegradation pathway mainly includes azo bond cleavage and electron attraction with a stronger electron affinity. This work not only proposes a deep insight into the biodegradation pathway of RR2 by employing BC550-AQS in an anaerobic biological system but also develops effective solid-phase RMs for efficient removal of contaminants from wastewaters by biological treatment.
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