Characterization and properties of polyethersulfone/ modified cellulose nanocrystals nanocomposite membranes
Introduction
The plant with scientific name of Glycyrrhiza glabra L. is a perennial herb of the legumes, which is important in the world due to the presence of medicinal and nutritional compounds in its roots and rhizomes and has been considered by pharmaceutical, food and even tobacco industries. Licorice root contains several compounds, such as fat reducing agents, various sugars (up to 18%), flavonoids with strong antioxidant activity, sterols, amino acids, gum, starch, essential oils and saponins. It has been proven that licorice root has an increasing effect on the secretion of serotonin and prostaglandin and consequently, has an antitumor activity in the stomach. The Commission E has confirmed the use of this plant in the congestion of the upper respiratory tract and duodenal ulcers [1]. Licorice root extracting plant produces a wastewater including dissolved organic matters such as some colored compounds (mostly natural organic compounds) which can be toxic, have hazardous effects on the organisms such as algae and deplete dissolved oxygen in the water. One practical treatment for this wastewater is physical separation of these colored compounds.
Chemical oxygen demand (COD) is one of the most important indicators of sewage pollution measurement. Sewage pollution is caused by suspended or soluble foreign materials that enter the water and contaminate it [2]. Obviously, the greater the amount of these materials in the wastewater, the more polluted it will be. The variety and number of these materials are so large that it is virtually impossible to measure each of them separately, so, their indirect measurement is necessary. One of the most appropriate ways is to determine the amount of oxygen needed for oxidation. Oxygenation is needed to oxidize any substance, and hence the greater the amount of oxidizing material, more oxygen will be required to perform oxidation [2]. Therefore, to determine the amount of external wastewater, instead of measuring them directly, the amount of needed oxygen for their oxidation (chemical oxygen demand, COD) is calculated. In fact, the greater the COD content of the sewage, the greater the amount of extraneous matter that contaminates it. Various methods such as absorption, coagulation and advanced oxidation are used for water purification [2]. Considering the high costs of research programs for impurities removal from wastewater, many of these methods are not used on a large scale. So, developing a new technique or combining different methods to achieve acceptable results in industrial applications is necessary [3]. One of the new processes for the removal of pollutants is membrane separation with the advantages of no need to phase change and energy consumption, higher efficiency compared to other techniques and ease of particles separation from very dilute solutions [4]. In membrane processes, color separation is often carried out with reverse osmosis (RO) and nanofiltration (NF). In order to get the best performance by separation, nanofiltration (NF) membranes seem to be effective due to their nanoporous structure that most of organic matters cannot pass through these nanopores [4,5]. The NF produces a high quality nano-filtrated permeate that is suitable for reuse in plant processes or discharge to the environment. Polymeric membrane, because of some advantages such as its straightforward pore forming mechanism, higher degree of flexibility, smaller footprints needed for installation and relatively low costs in comparison with inorganic membrane equivalents, is currently the most widely used membrane type for water purification [4,5].
Nanocomposite membranes are advanced membranes with dispersed nanomaterials in the polymer matrix, which can be used for gas-gas, liquid-liquid, and liquid-solid separations. Due to their promise of solving the trade-off relationship between selectivity and permeability and also, mitigating the problem of membrane fouling during water treatment, it has attracted growing attention and is considered as the cutting edge of creating the next generation of membranes with high performance [4,5]. Cellulose nanomaterials (CNM) are promising candidates for this purpose due to their numerous advantages such as renewability, biodegradability, inherent environmental inertness, high aspect ratio, specific strength and stiffness, low price, and good thermal stability. Moreover, CNC has easily functionalizable surface which allows the incorporation of chemical moieties and increase in binding efficiency of pollutants to the modified CNC [5]. Therefore, in this study, a nanocomposite membrane based on polyethersulfone (PES) and amine-functionalized cellulose nanocrystals was prepared, characterized and its potential in COD reduction and color removal from industrial wastewater of licorice processing was investigated. Efforts have been made to modify cellulose nanocrystals by new chemical materials and use them as an adsorbent for water purification and some literature on their adsorption performance have been published (Table 1). But to the best of our knowledge, loading (3-aminopropyl) triethoxysilane (APTES)-modified CNC in PES membranes has never been conducted before and there is no documented study in this direction.
Section snippets
Materials
APTES, glycial acetic acid, dimethyl sulfoxide and polyvinylpyrrolidone (PVP) were provided by Sigma-Aldrich Inc. (St Louis, MO, 120USA). The PES with Mw of 58,000 g/mol and density of 1.37 g/cm3 was purchased from BASF (Ludwigshafen, Germany). The CNC with the diameter of 10–25 nm and the length of 100–200 nm were prepared from cotton linter as described elsewhere [26]. After drying the samples at room temperature, transmittance electron microscope (TEM) analysis was conducted with an
Chemical structure of the nanocrystals
Fig. 3 shows the spectrum of the Fourier transform infrared of modified and unmodified cellulose nanocrystals and the respected peaks are shown in Table 2.
As can be seen from Table 2, the broad peak at 3500-3000 cm−1 and low intensity peak at 2899 cm−1 are attributed to hydroxyl groups and symmetrical stretching of CH, respectively. The peak at 1640 cm−1 is due to absorbed water. The peaks at 1433 cm−1 and 1363 cm−1 belong to the bending of CH2 and CH, respectively. The observed peaks at 1160 cm
Conclusions
The hypothesis of this study was to develop an environmental-friendly and simple process of surface modification of the cellulose nanocrystal by using (3-aminopropyl) triethoxysilane. APTES functionalized the cellulose nanocrystals which increases the available sites in the nanocomposite membranes that may responsible for efficient water impurities elimination. The FT-IR and EDX results showed that the CNC were modified successfully. In addition, the nanocomposite membranes characterization
Acknowledgments
The authors wish to acknowledge to Iran National Science Foundation for the financial support of the Research Project # 92043921 and also the University of Tehran.
References (27)
Climate change and challenges of water and food security
Int. J. Sustain Built. Environ.
(2014)- et al.
Nanocelluloses and their phosphorylated derivatives for selective adsorption of Ag+, Cu2+ and Fe3+ from industrial effluents
J. Hazard Mater.
(2015) - et al.
Adsorption of heavy metal ions from aqueous solution by carboxylated cellulose nanocrystals
J. Environ. Sci.
(2013) - et al.
Succinate-bonded cellulose: a regenerable and powerful sorbent for cadmium-removal from spiked high-hardness groundwater
J. Hazard Mater.
(2009) - et al.
Biosorption of Cd(II) from aqueous solution using xanthated nano banana cellulose: equilibrium and kinetic studies
Ecotoxicol. Environ. Saf.
(2013) - et al.
Adsorption of Cu(II) and Pb(II) onto diethylenetriamine-bacterial cellulose
Carbohydr. Polym.
(2009) - et al.
A novel adsorbent TEMPO-mediated oxidized cellulose nanofibrils modified with PEI: preparation, characterization, and application for Cu(II) removal
J. Hazard Mater.
(2016) - et al.
Improved metal affinity of chelating adsorbents through graft polymerization
Water Res.
(1999) - et al.
Surface chemical functionalization of cellulose nanocrystals by 3-aminopropyltriethoxysilane
Int. J. Biol. Macromol.
(2018) - et al.
Adsorption and removal of sulfonic dyes from aqueous solution onto acoordination polymeric xerogel with amino groups
Colloids Surf., A
(2015)
Innovations in nanotechnology for water treatment
Nanotechnol. Sci. Appl.
The future of seawater desalination: energy, technology, and the environment
Science
Effect of cellulose nanocrystals on performance of polyethersulfone nanocomposite membranes using electrospinning technique
Polym. Compos.
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