RESUMO
There has been a lot of attention on water pollution by dyes in recent years because of their serious toxicological implications on human health and the environment. Therefore, the current study presented a novel polyethylene glycol-functionalized graphene oxide/chitosan composite (PEG-GO/CS) to remove dyes from aqueous solutions. Several characterization techniques, such as SEM, TEM, FTIR, TGA/DTG, XRD, and XPS, were employed to correlate the structure-property relationship between the adsorption performance and PEG-GO/CS composites. Taguchi's (L25) approach was used to optimize the batch adsorption process variables [pH, contact time, adsorbent dose, and initial concentration of methyl orange (MO)] for maximal adsorption capacity. pH = 2, contact time = 90 min, adsorbent dose = 10 mg/10 mL, and MO initial concentration = 200 mg/L were found to be optimal. The material has a maximum adsorption capacity of 271 mg/g for MO at room temperature. With the greatest R2 = 0.8930 values, the Langmuir isotherm model was shown to be the most appropriate. Compared to the pseudo-first-order model (R2 = 0.9685), the pseudo-second-order model (R2 = 0.9707) better fits the kinetic data. Electrostatic interactions were the dominant mechanism underlying MO sorption onto the PEG/GO-CS composite. The as-synthesized composite was reusable for up to three adsorption cycles. Thus, the PEG/GO-CS composite fabricated through a simple procedure may remove MO and other similar organic dyes in real contaminated water.
RESUMO
The human body releases heat via four mechanisms: conduction, convection, evaporation, and radiation. The normal core temperature of the human body is around 37 °C, and metabolism may be negatively affected and enzymes/proteins may be destroyed if the core temperature rises above 45 °C. To prevent such overheating, we developed an evaporative-radiative-convective fabric which can control the personal microclimate of the human body through a cooling mechanism (evaporation of perspiration, air convection, and emission of heat radiation directly into the environment). In this work, we fabricated a thermo-moisture sensitive polyurethane/silica aerogel composite membrane which showed super evaporative and radiative effects and which can facilitate the convection process in the human body. We also fabricated a sensitive membrane-based textile which can cool down the human body by releasing body heat. The developed material possessed robust mechanical properties for the longevity of the material, high water-evaporative ability, and air permeability to provide comfort to the wearer. Microclimate-controlled clothing can release most of our body heat to the environment.
RESUMO
In order to provide thermo-physiological comfort to the wearer, textile materials should have some functional property like water-resistance or water vapor transmission (WVT), so that perspiration can evaporate and be transmitted from the body surface to the environment even in extreme weather conditions that require wind and rain proof. Shape memory polyurethane (SMPU) could possibly be a candidate; it is a functional textile material that meets such requirements. In this research, we synthesized a series of SMPUs, which are responsive materials, to test whether these coated cotton fabrics could provide thermal insulation with lower permeability at low temperature or low relative humidity (RH), and high permeability at room temperature or above, or high relative humidity with its water-resistance property. In this paper, we have proposed a segmented shape memory polyurethane for coated textiles in order to have a water-resistant textile with good water vapor transmitting ability.