Engineering Commercial TiO2 Powder into Tailored Beads for Efficient Water Purification

In this study, efficient commercial photocatalyst (Degussa P25) nanoparticles were effectively dispersed and stabilized in alginate, a metal binding biopolymer. Taking advantage of alginate’s superior metal chelating properties, copper nanoparticle-decorated photocatalysts were developed after a pyrolytic or calcination-sintering procedure, yielding ceramic beads with enhanced photocatalytic and mechanical properties, excellent resistance to attrition, and optimized handling compared to powdered photocatalysts. The morphological and structural characteristics were studied using LN2 porosimetry, SEM, and XRD. The abatement of an organic pollutant (Methyl Orange, MO) was explored in the dark and under UV irradiation via batch experiments. The final properties of the photocatalytic beads were defined by both the synthesis procedure and the heat treatment conditions, allowing for their further optimization. It was found that the pyrolytic carbon residuals enabled the adhesion of the TiO2 nanoparticles, acting as binder, and increased the MO adsorption capacity, leading to increased local concentration in the photocatalyst vicinity. Well dispersed Cu nanoparticles were also found to enhance photocatalytic activity. The prepared photocatalysts exhibited increased MO adsorption capacity (up to 3.0 mg/g) and also high photocatalytic efficiency of about 50% MO removal from water solutions, reaching an overall MO rejection of about 80%, at short contact times (3 h). Finally, the prepared photocatalysts kept their efficiency for at least four successive photocatalytic cycles.

Analytical Instrumentation Techniques of FT-IR, XRD, SEM, and EDX for Adsorption Methods of Ni2+ Ions onto Low Cost Adsorbent

The present study investigates the possible removal of Ni2+ ions from aqueous solution by using low-cost Hygrophila auriculata activated nano carbon (HA-ANC) as an adsorbent. The activated nano carbon had been prepared from Hygrophila auriculata stem waste as well; the raw material was carbonized with con. H2SO4 and activated by thermal action. Batch experiments were performed in order to calculate the percentage removal of Ni2+ ions for 90.737% at 60 oC. The properties of treated carbon and untreated carbon are compared using instrumental techniques such as FT-IR, XRD, SEM and EDX, which confirms Ni2+ ions adsorption onto HA-ANC. FT-IR showed that the surface of HA-ANC had more oxygen containing functional groups which enhanced the adsorption of Ni2+. XRD showed the nature of adsorbent, SEM images implies morphological deviance of before and after adsorption of Ni2+ onto HA-ANC and EDX showed that the C content of HA-ANC were higher than that of Ni2+/ HA-ANC.

Preliminary Study of Using Colloidal SiO2@ZrO2 Particles in Recovering Actinides from Water and Immobilizing them in a Glass-Ceramic

Actinides, which are toxic for humans, increased their presence in the hydrosphere over the last 80 years. Though actinide recovery from water and immobilization for safe storage is technically feasible, it remains a complex process. Herein, we preliminary studied SiO2@ZrO2 in recovering actinides from water and trapping them in a glass-ceramic upon thermal treatment. To simplify our experimental work, we surrogated radioactive actinides with stable cerium. In the first part of the work, we tested SiO2@ZrO2's ability to recover Ce from water in batch systems. Then, we thermally treated SiO2@ZrO2 with Ce to form a glass-ceramic. All batch experiments showed that SiO2@ZrO2 removes Ce from water. Moreover, all experiments show that SiO2@ZrO2 with Ce converts into a glass-ceramic upon thermal treatment. When heated up to 1000 °C, particles remained spherical, and Ce remained trapped within the structure of crystalline spheroids located between the outer surface and a 50 nm depth. When heated up to 1450 °C, sintering produced bigger particles than the original colloid, and Ce remained trapped within the structure of crystalline spheroids having a broad size distribution located everywhere in the particles.

Triacyl Glycerols from Yeast-Catalyzed Batch and Fed-Batch Bioconversion of Hydrolyzed Lignocellulose from Cardoon Stalks

The lipogenic ability of the yeast Solicoccozyma terricola DBVPG 5870 grown on hydrolyzed lignocellulose obtained from cardoon stalks was evaluated. Data on cell biomass, lipid production, and fatty acid profiles of triacylglycerols obtained in batch and fed-batch experiments were carried out at the laboratory scale in a 5L fermenter, and at two different temperatures (20 and 25 °C) were reported. The higher production of total intracellular lipids (13.81 g/L) was found in the fed-batch experiments carried out at 20 °C. S. terricola exhibited the ability to produce high amounts of triacylglycerol (TAGs) with a characteristic fatty acids profile close to that of palm oil. The TAGs obtained from S. terricola grown on pre-treated lignocellulose could be proposed as a supplementary source of oleochemicals. Indeed, due to the rising prices of fossil fuels and because of the environmental-related issues linked to their employment, the use of TAGs produced by S. terricola grown on lignocellulose could represent a promising option as a supplementary oleochemical, especially for biodiesel production.

Oxidative Degradation of Hazardous Benzene Derivatives by Ferrate(VI): Effect of Initial pH, Molar Ratio and Temperature

Two of the most hazardous benzene derivatives (HBD) that have polluted the aquatic environment are bromobenzene and chlorobenzene. Ferrate can degrade various pollutants quickly and efficiently without producing harmful byproducts. This study aims to determine the ability of ferrate to degrade harmful contaminants such as bromobenzene and chlorobenzene. A series of batch experiments were carried out, including for the molar ratio, initial pH solution, and temperature. The study was conducted at an initial pH of 3.6 to 9.6, a molar ratio of 2 to 8 and a temperature of 15 to 55 °C. The study will also examine the differences in functional groups in these pollutants. As a result of the experiments, the optimum conditions to oxidize HBD in a batch reactor was found to have an initial pH of 7.0, a molar ratio of 8, and a temperature of 45 °C, with a 10 min reaction time. Ferrate has a degradation ability against chlorobenzene greater than bromobenzene. The functional cluster in pollutants also significantly affects the degradation ability of ferrate. The results of the degradation experiment showed that ferrate(VI) could effectively oxidize hazardous benzene derivatives in a solution.

Study on the Adsorption Mechanism of Graphene Oxide by Calcareous Sand in South China Sea

To remove graphene oxide from wastewater, we used batch experiments with calcareous sand to recover GO. The adsorption properties and mechanisms of GO by calcareous sand were investigated by different characterization techniques. In this paper, the relationship between the coagulation of GO on calcareous sand and pH, calcareous sand content, GO initial concentration, and temperature was studied. The results show that calcareous sand can effectively adsorb GO from aqueous solution, the interaction of GO with calcareous sand achieved interaction equilibrium in 5 h, and the adsorption of GO by calcareous sand strongly depends on pH. The isotherm data fitted to a Langmuir equation. A possible mechanism can be expressed from FT-IR, XRD, Raman spectra, SEM, EDS, TEM, AFM, and XPS results. The test results indicate that calcareous sand is a potentially recoverable GO material.