RESUMEN
Chitosan (Ch) is a linear biodegradable natural carbohydrate polymer and the most appealing biopolymer, such as low-cost biodegradability, biocompatibility, hydrophilicity, and non-toxicity. In this case, Ch was utilized to synthesize AgCoFe2O4@Ch/Activated Carbon (AC) by the modified microwave-assisted co-precipitation method. The physical and chemical structure of magnetic nanocomposites was analyzed and characterized by Field Emission Scanning Electron Microscope (FESEM), Transmission electron microscopy (TEM), X-ray diffraction (XRD), Energy Dispersive Spectroscopy (EDS), Diffuse Reflection Spectroscopy (DRS), Value stream mapping (VSM), Fourier transform spectroscopy (FTIR) and BET. The effects of various parameters on the removal of dye (Acid Red18), including catalyst dose, dye concentration, pH, and time were studied. Results showed that the highest removal efficiencies were 96.68 % and 84 % for the synthetic sample and actual wastewater, respectively, in optimal conditions (pH: 3, the initial dye concentration: 10 mgL-1, the catalyst dose: 0.14 gL-1, time: 50 min). Mineralization, according to the COD analysis, was 89.56 %. Photocatalytic degradation kinetics of Acid Red 18 followed pseudo-first order and Langmuir-Hinshelwood with constants of kc = 0.12 mg L-1 min-1 and KL-H = 0.115 Lmg-1. Synthesized photocatalytic AgCoFe2O4@Ch/AC showed high stability and after five recycling cycles was able to remove the pollutant with an efficiency of 85.6 %. So, the synthesized heterogenous magnetic nanocatalyst AgCoFe2O4@Ch/AC was easily recycled from aqueous solutions and it can be used in the removal of dyes from industries with high efficiency.
Asunto(s)
Contaminantes Químicos del Agua , Catálisis , Contaminantes Químicos del Agua/química , Contaminantes Químicos del Agua/aislamiento & purificación , Nanocompuestos/química , Quitosano/química , Purificación del Agua/métodos , Compuestos Azo/química , Compuestos Azo/aislamiento & purificación , Reciclaje/métodos , Concentración de Iones de Hidrógeno , Aguas Residuales/química , Fotólisis , Nanopartículas de Magnetita/química , Cinética , Compuestos Férricos/química , Carbono/químicaRESUMEN
Chitosan is a potential renewable, versatile amino polysaccharide which has been approved by food and drug administration for use in food, cosmetics, pharmaceuticals and other industries. In order to determine if chitosan can be utilized in the development of colourful and multifunctional wool fabric without the need of toxic metal salt mordants, we have investigated the colouring, radical scavenging and antibacterial activity of wool dyed with tea extract polyphenols using chitosan as a green pre-treatment finishing agent. UV-vis analysis confirmed the optical properties of tea polyphenols, while Fourier-transform infrared spectroscopy (FT-IR), Scanning electron microscope (SEM) and Thermogravimetric analysis (TGA) spectroscopic characterizations demonstrated binding, surface morphology and thermal stability properties of chitosan coated wool. Colour spectrometry data obtained in terms of CIEL*a*b* values showed an outstanding effect of the chitosan pre-treatment. The Camellia sinensis (tea) extract dyed wool yielded interestingly elegant pale to golden yellowish colours with acceptable wash fastness properties. The chitosan gets its affinity for the wool via hydrogen bonding, electrostatic and van der Waals interactions. The results also showed that chitosan pre-treatment imparts excellent radical scavenging and antibacterial activity against E. coli and S. aureus, and thus offers new opportunities in the realm of natural dyeing.