Search

The occurrence of cellulose in wastewater is mostly due to the usage of lavatory tissue, anticipated to be about 30% of the produced domestic sewage. This makes the recovery of cellulosic substances from wastewater important as a resource valorization strategy. The cellulose recovery is highly recommended to be included in wastewater treatment plant (WWTPs), associated with the favorable environmental impression, flexible routes of application, and mature value chain. In the present review, a comprehensive map was drawn for the initial and transformational applications of cellulose in WWTPs. Typical microbial cultures found in wastewater, facilitating cellulose degradation in both aerobic and anaerobic cases were thoroughly reviewed. An outlook of commercialized technologies purposed for cellulose recovery has been provided, with prominence on rotating bed filter. The benefits of cellulose recovery from wastewater via various routes were also highlighted. [ABSTRACT FROM AUTHOR]

At the end of 19th century, the modification of silica has brought revolution in the field of nanocomposites and gained the attention of researchers again by the development of the mesoporous silica class. Silica when used with elastomers provides distinctive characteristics merging the superior properties of inorganic fillers, such as hardness, increased thermal strength, and mechanical stability along with the processability, elasticity, and plasticity of the organic polymers. When carbon black is treated with elastomers instead of silica, it provides greater level of reinforcement because the surface of silica is polar and hydrophilic, but it has greater tendency to adsorb moisture, which affects the ionization of silanol groups. The reason behind switching to silica is adverse effects of carbon black on environment. When silica is added in greater amount, it increases the viscosity of rubbers significantly. The high viscosity causes the processing extra difficult by generating excessive wear and tear over the processing equipment. The increase in viscosity is associated with the strong interaction among the silica particles. It has also been reviewed that the use of silica as filler in elastomers was hindered as far as bifunctional organosilanes were discovered. These are referred to as surface-modifying materials and are initiators for treating silica surfaces to make the filler compatible and friendly to elastomers. [ABSTRACT FROM AUTHOR]

In this work, LLDPE‐based composite films were prepared by melt mixing followed by compression molding to investigate the role of titanium oxide nanoparticles (TONPs) and/or multiwalled carbon nanotubes (CNTs) on the accelerated weathering samples (maximum of 39 days). Accelerating weathering caused the emerging of oxidation peaks in the FT‐IR spectra for LLDPE and LLDPE/TONPs. These peaks were not pronounced in the LLDPE/CNTs samples. The same prevention of oxidation peaks were noticed for the hybrid additives samples. Tensile properties decreased by exposing the composite samples to accelerating weathering. TONPs increased the tensile strength of the samples by 11.5% but deterioration of this property is the same as the pristine sample after accelerated weathering for 39 days. Addition of CNTs had negligible effect on the tensile strength but it kept the same approximate value of the original before the accelerated weathering (e.g., 23.2 MPa for 1 wt% of CNTs). CNTs also protected the samples even with the presence of TONPs because of the absorbance and antioxidants effects. The addition of CNTs into LLDPE network have not only retarded decomposition of LLDPE but also decreased catalytic activity of TONPs to activate degradation due to accelerated weathering. J. VINYL ADDIT. TECHNOL., 25:19–25, 2019. © 2018 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

CO2 emission from anthropogenic sources has raised worldwide environmental concerns and hence proficient energy paradigm has tilted towards CO2 capture. Membrane technology is one of the efficient technologies for CO2 separation since it is environmentally friendly, inexpensive, and offers high surface areas. Various approaches are discussed to improve membrane performance focusing mainly on permeability and selectivity parameters. Different types of fillers are incorporated to reach the Robeson's upper bound curve. In this review, polymer‐inorganic nanocomposite membranes for the separation of CO2, CH4, and N2 from various gas mixtures are comprehensively discussed. Metal organic frameworks (MOFs) and ionic liquid (ILs) mixed‐matrix membranes are also considered. Membrane technology is considered as an efficient, environmentally friendly, and inexpensive technology for CO2 separation. Various approaches to improve membrane performance are reviewed with the focus on permeability and selectivity parameters. Polymer‐inorganic nanocomposite membranes, metal organic frameworks, and ionic liquid mixed‐matrix membranes are also discussed and evaluated. [ABSTRACT FROM AUTHOR]

We evaluated the thermochemical properties and suitability of a variety of lignocellulosic biomass residues in Pakistan for energy production. Proximate, ultimate and calorific value analyses were performed to know the energy perspective, whereas thermogravimetric analysis was used to study the decomposition behavior of biomass samples under pyrolysis conditions. The moisture content, volatile matter, fixed carbon and ash content in the biomass samples were found within the range of 4.38–5.69%, 63.25–80.53%, 7.97–23.13%, and 7.12–14.35%, respectively. The range of carbon, hydrogen, and oxygen content was reported as 35.83–47.23%, 5.2–6.56%, and 45.6–58.55%, respectively. Lower values of sulfur and nitrogen content amongst the samples indicated that the biomass was environmentally friendly in terms of energy production. The heating value of the biomass was reported in the range of 15.20–18.44 MJ/kg. Fourier transform infrared spectroscopy showed the existence of hydroxyl, aldehydes, ketones, aromatic compounds, carbonyl compounds, ether, and halogen groups. Orange leaf biomass indicated a greater potential in producing bio-oil, whereas the horticulture biomass and mango leaves may have greater potential for biochar. [ABSTRACT FROM AUTHOR]

Enhanced mechanical and barrier properties are of special interest in food packaging industries, in which uniform dispersion of nanoparticles in polymers confers considerable improvement in these properties. In this study, maleic anhydride grafted polyethylene (MAPE) and ethylene vinyl acetate (EVA) compatibilised low density polyethylene/montmorillonite (LDPE/MMT) nanocomposite films were prepared with different concentrations of the compatibilisers by melt mixing technique. The delamination of MMT layers was evidenced from X-ray diffraction results that suggested an increase in the interlayer distance with the addition of compatibilisers, where MAPE is the better compatibiliser in delaminating MMT platelets in LDPE/MMT nanocomposites compared to EVA. The mechanical and barrier properties of compatibilised LDPE/MMT nanocomposites were better than uncompatibilised nanocomposites. The best improvement in tensile strength, tear strength and oxygen barrier were observed for LDPE/MMT/MAPE nanocomposites. However, the best improvements in elongation at break were seen for the LDPE/MMT nanocomposites compatibilised with EVA. Conclusively, MAPE compatibiliser is more effective in delaminating MMT platelets in LDPE/MMT nanocomposites, enhancing the mechanical and barrier properties of the nanocomposites. Results revealed that the optimum content of MAPE in terms of mechanical and barrier properties is 3 phc. The enhanced tensile and barrier properties of LDPE/MMT films with the incorporation of MAPE suggest a great potential of these nanocomposite films in food packaging. [ABSTRACT FROM AUTHOR]

In this work, different quantities of TiO 2 incorporated into TiO 2 -KIT6 nanostructured catalysts were considered to improve the photocatalytic abatement of volatile organic compounds (VOCs; ethylene, propylene) at ambient temperature. The best optimized activity and stability of the catalysts toward(s) ethylene and propylene degradation has been shown for 30 wt% TiO 2 , while the worst conversion has been observed for a 90 wt% TiO 2 loading. This was likely due to the dispersion and stabilization of the anatase TiO 2 with 30 wt% on KIT-6, which in turn allowed more VOCs adsorption and better light penetration than 90% TiO 2 /KIT-6 in which it showed a bulk phase and large agglomerates with light penetration limitations. VOC abatement has been found to be not only influenced directly by the dispersed TiO 2 contents but also by the calcination temperatures, and 500 °C has been found to be the best calcination condition to achieve the highest propylene conversion. The optimized nanostructured photocatalyst developed for ethylene and propylene, could also be promising candidate for other VOCs and different applications. [ABSTRACT FROM AUTHOR]

Rice husk (RH)/montmorillonite (MMT) hybrid filler-filled low-density polyethylene nanocomposite films were prepared by extrusion blown film. RH was used as a biodegradable filler in various concentrations (2, 5, and 7 parts per hundred composite), while the amount of MMT was held constant at 2 wt%. Delamination of MMT platelets and distribution of RH were investigated by X-ray diffraction and scanning electron microscopy. Diffractograms revealed the formation of intercalated structures, regardless of the RH content. Barrier properties revealed that MMT platelets have the potential to retard the diffusion of permeating molecules while, on the other hand, barrier efficiency of MMT is balanced by the subsequent incorporation of RH in RH/MMT hybrid filler-filled composite films. Despite an increase in permeability, the selectivity ratio (CO2/O2 permeability) increased with increasing RH contents in the hybrid filler-filled composite films showing the potential of these films in the development of modified atmosphere for fresh fruits and vegetables. The colonization of fungus and formation of holes as observed in micrographs of the test samples subjected to soil burial revealed that the biodegradation rate increased with the incorporation of RH in the hybrid composites. The composite films with higher contents of RH in hybrid filler are also more biodegradable than those having lower contents. Addition of RH contents in the hybrid filler increased the tensile modulus, while decreasing the tensile and tear strength. Addition of RH in the hybrid filler increased the melting and crystallization temperatures of the resulting nanocomposite films as well. J. VINYL ADDIT. TECHNOL., 23:162-171, 2017. © 2015 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

Montmorillonite (MMT)/rice husk (RH) hybrid filler-filled low-density polyethylene (LDPE) nanocomposite films, containing 0, 2, 3, 4, 5, and 6 wt% MMT (based on the total weight) were prepared by extrusion blown film. The films were characterized by morphological, mechanical, oxygen (O2) barrier, and thermal properties. The delamination of MMT layers evidenced from X-ray diffraction results suggests an increase in the interlayer distance and shows intercalated structure of the nanocomposites. Adding MMT did not adversely affect the interfacial morphology, as confirmed by scanning electron microscopy. Addition of MMT into the LDPE/RH system improved the mechanical and O2 barrier properties. For instance, tensile strength, tensile modulus, and tear strength increased by 8, 10, and 5%, respectively, with the addition of 3 wt% MMT. Further, the O2 barrier of the composite films improved more than twofold by adding 4 wt% MMT. Initial degradation temperature of LDPE/RH composites increased with the incorporation of MMT suggesting that the nanocomposites are more thermally stable than LDPE/RH composites. [ABSTRACT FROM AUTHOR]

Rice husk and nanoclay (montmorillonite)-filled low-density polyethylene composite films were prepared by extrusion blown film. Maleic anhydride-modified polyethylene was used as compatibiliser in various concentrations ranging from 0 to 8 parts per hundred. X-ray difractograms showed an increase in interlayer spacing of montmorillonite from the use of compatibiliser when compared to the uncompatibilised composites; an increase of 20, 33, 36 and 38% for 2, 4, 6 and 8 parts per hundred, respectively, of maleic anhydride-modified polyethylene. With the incorporation of maleic anhydride-modified polyethylene, a better dispersion of the fillers was also achieved, as confirmed by scanning electron microscopy. The compatibilised composite films showed improved tensile and barrier properties. The addition of 4 parts per hundred of the compatibiliser resulted in an improvement by 22% in tensile strength. Furthermore, oxygen barrier property of the composite films improved more than twofold by adding 4 parts per hundred of maleic anhydride-modified polyethylene. This improvement in tensile and barrier properties is due to an increase in the interfacial adhesion between the fibre and matrix and better dispersion of impermeable nanoparticles. [ABSTRACT FROM PUBLISHER]