Nanocellulose and Polycaprolactone Nanospun Composite Membranes and Their Potential for the Removal of Pollutants from Water

Abstract

A composite membrane based on polycaprolactone (PCL) and cellulose nanofibers (CNF) with different compositions was prepared using the electro-spinning method, with the objective of developing organic membranes with good mechanical properties to remove contaminants from water. Water is a resource of primary importance for life and human activities. In this sense, cellulose obtained from agave bagasse and polycaprolactone nanofibers was used to prepare membranes that were tested by filtering tap water. The membranes obtained presented a porosity and structure on a nanometric scale. The water quality variables evaluated after filtration with the PCL/CNF membranes showed 100% turbidity removal, 100% conductivity, and heavy metal removal of the order of 75% to 99% for iron and chromium. CNF comprises biowaste derived from tequila production, and it has added value. Electro-spun CNF and PCL membranes can be applied as a "green" and eco-friendly filtration system for water purification.Molecules 2020, 25, 683 2 of 13 about 40% (wet basis) of over 1000 tons of agave grown in Mexico [11]. The availability of such large quantities of agave bagasse [9] poses serious disposal problems, since most of the biomass ends up in clandestine dumps (due to little environmental regulation), causing adverse effects on the fertility of farmland [12], contamination by leachates, and phytosanitary risks due to the inadequate incorporation of this material into the soil [13]. Chemically, agave bagasse is 44.5% cellulose, 25.3% hemicellulose, and 20.1% lignin [7]. Taking advantage of these constituents, there have been many efforts to use agave bagasse for various applications, e.g., the production of biopolymers [14,15], composting [16], animal nutrition [17], generation of biofuels [10,18], reinforcement materials [19], etc. More recently, agave bagasse is being explored for the production of cellulose nanofibers and nanocrystals [7,8,20,21] to further diversify the utilization of this biowaste. On the other hand, electro-spinning of biopolymers has become popular in the manufacture of nanofibers for a variety of added value applications, such as tissue engineering, drug release, sensors, and air and liquid filtration systems [22][23][24][25][26].Our main interest in electro-spinning agave cellulose nanofibers was to produce membranes that can retain suspended particles in water (due to the diameter of the fibers), a membrane with high porosity and good surface area properties. However, the main challenge with the preparation of electro-spun agave cellulose was the poor solubility of cellulose that was to be dispersed into an electro-spinnable liquid [24]. We overcame the poor solubility challenge by dissolving agave cellulose in dimethylformamide (DMF) and blending with polycaprolactone to prepare a composite electro-spun blend, subsequently producing electro-spun nanocellulose and polycaprolactone membranes. The main objective of using a copolymer blend was to improve technical properties, such as contaminant retention capacity, therma...

Impact of poly(ε‐caprolactone) on the thermal, dynamic‐mechanical and crystallization behavior of polyvinylidene fluoride/poly(ε‐caprolactone) blends in the presence of KIT‐6 mesoporous particles

“…For PCL, absorption bands at 2945 and 2865 cm −1 for asymmetric and symmetric CH 2 stretching bonds were presented, respectively.CH 2 bending was responsible for the peaks at 1471,1396, 1364 cm −1 , and the sharp peak located at 1720 cm −1 was assigned to carbonyl groups (C═O). CO and CC stretching bonds in the crystalline phase of PCL appeared at 1294 cm −1 , and absorption bands at 1240and 1166 cm −1 were attributed to asymmetric and symmetric COC stretching bonds, respectively 56,57 . According to the literature, 58–60 neat PVDF exhibited characteristic peaks at 795 and 1401 cm −1 assigned to the deformed vibration of CH 2 groups.…”

“…As can be seen in Figure 5A, neat PVDF shows crystalline peaks at 2 θ =18.5° and 20.3°, which belong to α (020) and β (200) crystal planes, respectively 19,58 . On the other hand, characteristic peaks appeared at 2 θ = 21.0° and 23.3°, corresponding to the (110) and (200) crystallographic planes of the PCL crystals, respectively 56,57 whose intensity reduced with decreasing PCL content. The obtained results indicate the presence of PVDF β ‐phase in the blends.…”

Cellulose Nanofibers as Functional Biomaterial from Pineapple Stubbles via TEMPO Oxidation and Mechanical Process

“…For example, CNC are shorter and smaller and have better resistance properties and greater crystallinity than cellulose nanofibers and can be used as reinforcement materials [24]. Cellulose nanofibers can crosslink and form high strength nanostructures for other applications [27]. Accordingly, the novelty of this research is producing CNF from pineapple leaves white cellulose bleached and unbleached using an oxidative pretreatment with TEMPO followed by mechanical combination of grinding and microfluidization process.…”

Antibacterial and Biodegradable Electrospun Filtering Membranes for Facemasks: An Attempt to Reduce Disposable Masks Use

“…Finally, the bands at 1470, 1240 and 1169 cm −1 are attributed to C-C bending, asymmetric C-O-C stretching and symmetric C-O-C stretching, respectively. The band at 1294 cm −1 is from C-O and C-C stretching in the crystalline phase, while the one at 1105 cm −1 corresponds to C-O and C-C stretching in the amorphous phase [33,34]. Considering the spectrum of PCL membranes functionalized with PEG-coated Ag NPs, besides the characteristic bands of PCL, the appearance of a new one at 887 cm −1 is observed, which is attributed to PEG polymer [26,28].…”