Use of copper-functionalized cotton waste in combined chemical and biological processes for production of valuable chemical compounds.

Cotton textiles modified with copper compounds have a documented mechanism of antimicrobial action against bacteria, fungi, and viruses. During the COVID-19 pandemic, there was pronounced interest in finding new solutions for textile engineering, using modifiers and bioactive methods of functionalization, including introducing copper nanoparticles and complexes into textile products (e.g. masks, special clothing, surface coverings, or tents). However, copper can be toxic, depending on its form and concentration. Functionalized waste may present a risk to the environment if not managed correctly. Here, we present a model for managing copper-modified cotton textile waste. The process includes pressure and temperature-assisted hydrolysis and use of the hydrolysates as a source of sugars for cultivating yeast and lactic acid bacteria biomass as valuable chemical compounds.

Zn Modification of Pd/TiO2/Ti Catalyst for CO Oxidation.

The main goal of this study was to modify the activity of Pd/TiO2/Ti catalyst in the reaction of CO oxidation by the addition of Zn. Plasma electrolytic oxidation (PEO) of Ti wire was conducted to produce a uniform porous layer of TiO2. A mixture of Pd and Zn was then introduced by means of adsorption. After reduction treatment, the activity of the samples was examined by oxidation of 5% CO in a temperature range from 80-350 °C. Model catalysts with sufficient amounts of the metals for physico-chemical investigation were prepared to further investigate the reaction between Pd and Zn during CO oxidation. The structures and compositions of the samples were investigated using scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS), time-of-flight secondary ion mass spectrometry (TOF-SIMS), inductively coupled plasma mass spectrometry (ICP-MS), Fourier transform infrared (FTIR), and X-ray diffraction (XRD). Modification of Pd/TiO2/Ti catalyst by Zn with a Pd:Zn atomic ratio of 2:1 decreased the temperature of complete CO oxidation from 220 °C for Pd/TiO2/Ti to 180 °C for Pd-Zn/TiO2/Ti. The temperature of 50% CO conversion on Pd-Zn(2:1)/TiO2/Ti was around 55 °C lower than in the reaction on monometallic Pd catalyst. The addition of Zn to the Pd catalyst lowered the binding energy of CO on the surface and improved the dissociative adsorption of oxygen, facilitating the oxidation of CO. FTIR showed that the bridging form of adsorbed CO is preferred on bimetallic systems. Analysis of the surface compositions of the samples (SEM-EDS, TOF-SIMS) showed higher amounts of oxygen on the bimetallic systems.

CO Oxidation over Pd Catalyst Supported on Porous TiO2 Prepared by Plasma Electrolytic Oxidation (PEO) of a Ti Metallic Carrier.

A porous TiO2 layer was prepared with the plasma electrolytic oxidation (PEO) of Ti. In a further step, Pd was deposited on the TiO2 surface layer using the adsorption method. The activity of the Pd/TiO2/Ti catalyst was investigated during the oxidation of CO to CO2 in a mixture of air with 5% CO. The structure of the catalytic active layer was studied using a scanning electron microscope equipped with an energy dispersive spectrometer (SEM-EDS), time-of-flight secondary ion mass spectrometry (TOF-SIMS), inductively coupled plasma mass spectrometry (ICP-MS), and X-ray diffraction (XRD). The PEO process provided a porous TiO2 layer with a uniform thickness in the range of 5-10 µm, which is desirable for the production of Pd-supported catalysts. A TOF-SIMS analysis showed the formation of Pd nanoparticles after the adsorption treatment. The conversion of CO to CO2 in all samples was achieved at 150-280 °C, depending on the concentration of Pd. The composition of Pd/ TiO2/Ti was determined using ICP-MS. The optimum concentration of Pd on the surface of the catalyst was approximately 0.14% wt. This concentration was obtained when a 0.4% PdCl2 solution was used in the adsorption process. Increasing the concentration of PdCl2 did not lead to a further improvement in the activity of Pd/ TiO2/Ti.

A Model Procedure for Catalytic Conversion of Waste Cotton into Useful Chemicals.

Cotton is grown in about 90 countries and accounts for 24% of the fibers used in the global production of textiles. In 2018/2019, 25.8 Mt of cotton were produced around the world. Since this natural product consists mainly of cellulose, it can be used as a raw material in the so-called "sugar economy". This paper discusses a model procedure for thermally assisted acidic hydrolysis of cotton into glucose and subsequent oxidation of the glucose into calcium gluconate over Pd-Au/SiO2 catalyst. In the first step, H2SO4 was used as a catalyst for hydrolysis. The cotton hydrolysates were neutralized using CaCO3 and applied as a substrate in the second step, where glucose was oxidized over Pd-Au/SiO2 prepared by ultrasound assisted co-impregnation. With the appropriate Au/Pd molar ratio, small crystallites of palladium and gold were created which were active and selective towards the formation of gluconate ions. This approach to the transformation of glucose represents as a viable alternative to biological processes using fungal and bacterial species, which are sensitive to the presence of inhibitors such as furfurals and levulinic acid in hydrolysates.

Butanol Synthesis Routes for Biofuel Production: Trends and Perspectives.

Butanol has similar characteristics to gasoline, and could provide an alternative oxygenate to ethanol in blended fuels. Butanol can be produced either via the biotechnological route, using microorganisms such as clostridia, or by the chemical route, using petroleum. Recently, interest has grown in the possibility of catalytic coupling of bioethanol into butanol over various heterogenic systems. This reaction has great potential, and could be a step towards overcoming the disadvantages of bioethanol as a sustainable transportation fuel. This paper summarizes the latest research on butanol synthesis for the production of biofuels in different biotechnological and chemical ways; it also compares potentialities and limitations of these strategies.

Concept for Recycling Waste Biomass from the Sugar Industry for Chemical and Biotechnological Purposes.

The objective of this study was to develop a method for the thermally-assisted acidic hydrolysis of waste biomass from the sugar industry (sugar beet pulp and leaves) for chemical and biotechnological purposes. The distillates, containing furfural, can be catalytically reduced directly into furfurayl alcohol or tetrahydrofurfuryl alcohol. The sugars present in the hydrolysates can be converted by lactic bacteria into lactic acid, which, by catalytic reduction, leads to propylene glycol. The sugars may also be utilized by microorganisms in the process of cell proliferation, and the biomass obtained used as a protein supplement in animal feed. Our study also considered the effects of the mode and length of preservation (fresh, ensilage, and drying) on the yields of furfural and monosaccharides. The yield of furfural in the distillates was measured using gas chromatography with flame ionization detector (GC-FID). The content of monosaccharides in the hydrolysates was measured spectrophotometrically using enzymatic kits. Biomass preserved under all tested conditions produced high yields of furfural, comparable to those for fresh material. Long-term storage of ensiled waste biomass did not result in loss of furfural productivity. However, there were significant reductions in the amounts of monosaccharides in the hydrolysates.

Ozonation as an effective way to stabilize new kinds of fermentation media used in biotechnological production of liquid fuel additives.

BACKGROUND: Intermediates from processing sugar beets are considered an attractive feedstock for ethanol fermentation due to their high fermentable sugar content. In particular, medium prepared from raw sugar beet juice seems to be suitable for use in fermentation processes, but it is microbiologically unstable and requires sterilization. RESULTS: This study investigates the effect of ozone treatment on the activity of microbial cells from Bacillus subtilis, Leuconostoc mesenteroides, Geobacillus stearothermophilus, Candida vini, and Aspergillus brasiliensis in raw sugar beet juice. Raw sugar beet juice contaminated with 10(5) cfu/mL of the microbial strains was treated with gaseous ozone (ozone concentration in the oxygen stream 0.1 g O3/L O2, flow rate 6 L/h, 10-30 min, 18-20 °C). The number of microflora decreased to 0 cfu/mL after 30 min of ozone treatment in all studied samples. CONCLUSIONS: Medium prepared from raw sugar beet juice and sterilized by ozonation is suitable for use in fermentation processes.