Valorization Of Industrial By-products Research Articles

Thermal activation of basic oxygen furnace slag as a heterogeneous catalyst in transesterification: Characterization and catalytic activity studies

The valorization of industrial by-products has garnered significant attention in recent years due to its potential to enhance sustainability and economic efficiency within various sectors. Basic Oxygen Furnace slag (BOF-S), a by-product generated in the steelmaking process characterized by its complex composition, presents an opportunity for waste management and resource recovery. This study investigates the potential of BOF-S as a catalyst in converting waste cooking oil to biodiesel via the transesterification reaction. To improve its efficiency, BOF-S was calcined at 850 °C (BOF-S 850), and 1000 °C (BOF-S 1000), for 5 h. The BOF-S was characterized using XRF, N2 sorption, XRD, TGA-DSC, SEM-EDS and FTIR. The characterization techniques showed that the BOF-S 850 had superior characteristics as a catalyst: rough surface, increased pore size and more active basic sites compared to the BOF-S and the BOF-S 1000 slag samples. The transesterification reaction was conducted at a methanol: oil ratio of 20:1, a catalyst loading of 20 wt %, a reaction time of 12 h, a reaction temperature of 60 °C, and a stirring speed of 750 rpm. The findings established that the BOF-S 850 was the best catalyst, with a 90.77 % biodiesel yield and was able to sustain a maximum of two transesterification cycle runs.

Sericin-TiO2 nanocomposite treated cotton fabrics for enhanced antibacterial and self-cleaning properties

The valorization of industrial byproducts is rising as a new dawn and has become a creative area of research for the scientists. Sericin is being a good resource of starting materials since it can be recovered and recycled. The research aimed to modify cotton fabric by sericin-TiO2 nanocomposite (STNc) for enhancement its antibacterial and self-cleaning properties. STNc were prepared using tetraisopropylorthotitanate (TIOT) and sericin with proportions 2:1, 2:2 and 1:2. The obtained STNc possesses anatase phase of TiO2 nanoparticles having an average 22.9 nm particle sizes. The STNc coated cotton samples were prepared with three different weight fractions of STNc and citric acid (2:1:2, 2:2:1 and 1:2:2). The incorporation of STNc onto cotton fabric was examined by FTIR spectroscopy, scanning electron microscopy (SEM), and X-ray diffraction (XRD) analyses. The antibacterial activity of STNc coated cotton fabrics was investigated against drug resistant bacterium viz. Staphylococcus aureus, Pseudomonas 4A and Escherichia coli. The STNc coated cotton fabric exhibited effective resistance against Escherichia coli and Staphylococcus aureus. The antibacterial properties of STNc coated cotton fabrics were depended with the fraction of STNc. The uncoated and STNc coated cotton fabrics were stained with coffee and then irradiated on sunlight for 0, 30, 60, 90 h and UV light for 2, 4, 6, 8, 10 h. A noticeable decrease in the coffee stain's appearance was observed after 90 h sunlight and 10 h UV light exposure for STNc coated cotton fabric. The reusability of photo exposed samples was evaluated by FTIR spectroscopy.

Valorization of a Steel Industrial Co-Product for the Development of Alkali-Activated Materials: Effect of Curing Environments

Abstract While natural resources are becoming scarce and climate change is accelerating, the recovery and recycling of wastes and by-products is an effective way to deal with the economic and ecological constraints of recent decades. The valorization of industrial by-products in civil engineering is a common practice either by their incorporation during the manufacture of Portland cements or as a partial replacement of cement during the production of concrete. The present work aims to develop waste-based alkali-activated materials WAAMs intended for civil engineering applications as a potential alternative to cement-based materials. A steel industrial by-product called commonly granulated blast furnace slag GBFS was used alone as a solid CaO-rich precursor; two alkaline activators such us sodium silicate (Na2SiO3) and sodium hydroxide (NaOH) were used separately for the production of two-part alkali-activated materials. Besides the microstructure analysis of the hardened samples, the influence of activator/precursor mass ratio, NaOH molarity, and two curing environments (Room temperature and 60°C) on the compressive strength, water accessible porosity, mass loss, and drying shrinkage were assessed. The results showed that a high Liquid/Solid ratio leads to a decrease in the compressive strength of the samples, while high NaOH molarity significantly improves the mechanical properties by reducing the porosity of the specimens. Moreover, alkaline silicate activator provides higher compressive strengths compared to the alkaline hydroxide activator, especially when the samples were cured at room temperature where a maximum 28days-compressive strength value of 105.28 MPa was achieved. For the samples activated using sodium hydroxide solution, the results revealed that their curing at 60°C promotes obtaining high initial-compressive strengths (7 days) before decreasing subsequently as a function of the curing time. As an indication, at high alkaline concentration (NaOH = 9M), a mechanical strength decline of 21% was recorded between a curing time of 7 to 28 days. Moreover, curing at 60°C induced high porosity, significant mass loss and high drying shrinkage. SEM analysis highlighted a dense, homogeneous microstructure without apparent defects, in particular for the samples where the alkali silicate activator was used.

Valorization of industrial by-products through bioplastic production: defatted rice bran and kraft lignin utilization

Abstract The objective of this study was to develop a bioplastic from industrial by-products. Commercial defatted rice bran (DRB) was extruded with 0–30% kraft lignin (KL) as a filler and 30% glycerol as a plasticizer. Firstly, the effect of extrusion temperature on the plasticized DRB’s processability was determined. Increasing the die extrusion temperature from 100°C to 150°C improved the extrudability by decreasing the die pressure and motor current. Subsequently, the effect of KL on plasticized DRB was studied. The addition of 10–30% KL improved DRB processability. The addition of 30% KL markedly lowered the die pressure in comparison to using a 150°C extrusion temperature. Moreover, KL addition decreased DRB viscosity determined by a capillary rheometer. These results were coherent with a decreased storage modulus in a rubber state and an increased tan δ height determined by a dynamic mechanical thermal analyzer (DMA). However, n values of DRB with 10–30% KL could not be explained by a simple mixing rule. This may be attributed to the interaction between DRB and KL, as shown by Fourier transform infrared (FTIR) spectra. KL addition increased Young’s modulus and the glass transition temperature (T g) of plasticized DRB. Therefore, blending DRB with KL is an effective way to improve polymer flowability at the processing temperature and mechanical properties at ambient temperature.

Valorization of industrial by-products: development of active coatings to reduce food losses

An active coating based on soy protein, obtained as by-product from soy oil production, was used to extend the shelf-life of beef patties. On the one hand, the use of industrial by-products contributes to valorize by-products by preparing value added products. On the other hand, the extension of food shelf-life contributes to the reduction of food looses and could allow the use of lower amounts of packaging, reducing plastic waste. With this regard, some physicochemical and textural parameters of beef patties were analyzed in this study. The incorporation of the soy protein-based coating delayed food oxidation, prevented moisture loss and improved textural parameters of beef patties. Since the appearance and texture of food are very relevant aspects when purchasing food products, the improvement of these quality attributes showed in this study highlights the potential of using active coatings, such as the soy protein-based coatings analyzed in this work. In particular, their use would bring social benefits such as shelf-life extension and thus, reduction of food losses, but also the possibility of reducing the amount of packaging used to preserve food and the environmental and economical benefits associated with this reduction of packaging.