Novel Sodium Alginate/Polyvinylpyrrolidone/TiO2 Nanocomposite for Efficient Removal of Cationic Dye from Aqueous Solution

The combination of adsorption and photodegradation processes is an effective technique for the removal of dye contaminants from water, which is motivating the development of novel adsorbent-photocatalyst materials for wastewater treatment. Herein, novel nanocomposite porous beads were developed using titanium dioxide (TiO2) nanotubes embedded in a sodium alginate (SA)/polyvinylpyrrolidone (PVP) matrix using calcium chloride solution as a crosslinker. The prepared nanocomposite beads’ performance was examined as an adsorbent-photocatalyst for the breakdown of methylene blue in aqueous solutions. Several operation factors influencing the dye decomposition process, including photocatalyst dosage, illumination time, light intensity, and stability were investigated. The findings demonstrated that the removal activity of the beads changed with the TiO2 weight ratio in the composite. It was found that SA/PVP/TiO2-3 nanocomposite beads presented the greatest deterioration efficiency for methylene blue dye (98.9%). The cycling ability and reusability of the prepared SA/PVP/TiO2 nanocomposite beads recommend their use as efficient, eco-friendly materials for the treatment of wastewaters contaminated with cationic dyes.

Numerical Investigation of a Designed-Inlet Optofluidic Beam Splitter for Split-Angle and Transmission Improvement

The beam splitter is one of the important elements in optical waveguide circuits. To improve the performance of an optofluidic beam splitter, a microchannel including a two-stage main channel with divergent side walls and two pairs of inlet channels is proposed. Besides, the height of the inlets injected with cladding fluid is set to be less than the height of other parts of the microchannel. When we inject calcium chloride solution (cladding fluid) and deionized water (core fluid) into the inlet channels, the gradient refractive index (GRIN) developed in fluids flowing through the microchannel split the incident light beam into two beams with a larger split angle. Moreover, the designed inlets yield a GRIN distribution which increases the light collected around the middle horizontal line on the objective plane, and so enhances the transmission efficiency of the device. To demonstrate the performance of the proposed beam splitter, we use polydimethylsiloxane to fabricate the microchannel. The results obtained by simulation and experiment are compared to show the effectiveness of the device and the validity of numerical simulation. The influence of the microchannel geometry and the flow rate ratio on the performance of the proposed beam splitter is investigated.

Effect of Temperature on Calcium Carbonate Precipitation in Biomimetic Calcium Chloride Solution

In the present work, the effect of temperature on calcium carbonate precipitation in the biomimetic calcium chloride solution was investigated. A spontaneous calcium carbonate precipitate was formed in the biomimetic calcium chloride solution as a result of the carbon dioxide hydration process. The reaction was conducted at different temperature range vary from 30°C to 100°C. The mass of the calcium carbonate precipitate and the pH solution was measured in the study. The finding indicated that an increment of the temperature has led to the fast pH reduction of the solutions to 7.0. However, the process has retarded the calcium carbonate precipitation process. The optimum temperature for higher calcium carbonate precipitation has occurred at the temperature range of 47.5°C – 65°C which gave the highest calcium carbonate precipitate at 0.121g. The addition of Tris buffer into the calcium chloride solution in this study did not gave an inhibition effect on the calcium carbonate precipitate. Based on the results, an operating condition at 47.5°C – 65°C was recommended to be used in mineral carbonization of CO2 using the biomimetic calcium chloride solution.

Sterilization of Male Dogs by Intra-testicular Administration of Calcium Chloride Solution

Background: Chemical castration is one of the methods of non surgical contraception which has been suggested as a fast and low cost alternative to control a wide range of canine population.Methods: The potency of intra-testicular 20% calcium chloride solution was tested in 12 fertile, healthy and stray adult male dogs. Dogs were divided randomly into two groups, consisting six animals in each. The animals of group-I were administered intra-testicular 1.0 ml of 20% calcium chloride solution. Bilateral intra-testicular injection was performed using 21 gauge needle directed from the caudo-ventral aspect of each testis approximately 1 cm from the cauda epididymis and towards the dorso-cranial aspect of testis as per the procedure adopted by Jana and Samanta (2007). In group-II, 1.0 ml of normal saline was injected intra-testicular as placebo. Its efficacy was assessed by testicular morphometry, scrotal circumference (on day 0, 7, 15 and 30), histo-morphology (on day 0 and 30) and serum testosterone assay (on day 0, 15 and 30 of treatment).Result: The testicular morphometry of both the testicles was found to be increased size of testes significantly on day 7 in the treatment group as compared to day 0 and then decreased gradually and significantly on day 15 and 30. Histo-morphological study revealed significant changes including complete derangement of seminiferous tubules on day 30 post-treatment. Out of six animals the testes of four animals represented complete destruction of outline of seminiferous tubules. The germinal epithelium and Leydig cells were degenerated and parenchyma was replaced by fibro-collagenous tissue which was evident by the presence of numerous fibrocytes and fibroblast. There was no evidence of mature germ cells in section of both the testes. In some areas small blood capillaries were observed which may indicate neo-vascularisation. Discrete inflammatory infiltration of leucocytes was also observed in the parenchyma. Decrease in serum testosterone level after the end of study, i.e., day 30 indicated degeneration of Leydig cells. It can be concluded that 20% calcium chloride solution has a potential for testicular degeneration and thus sterilization of male dogs.

Optimization of Immobilization Condition of Protease Extracted from Silver Catfish (Pangasius Sutchi) Viscera in Calcium Alginate by using Response Surface Methodology (RSM)

The term of immobilized enzymes refers to enzymes that physically entrapped within pores of synthetic or natural polymeric network with no alteration in the enzyme catalytic activities. In this study, protease from silver catfish viscera have been extracted, partially purified by acetone precipitation method and immobilised in the calcium alginate beads. Various range of sodium alginate (1–5% w/v) and calcium chloride (0.1–0.5 M) concentrations were used for the optimization purpose. Proteolytic activity of the protease in the alginate beads was measured as a response to the independent variables by using casein as a substrate. The highest actual and predicted proteolytic activities were at run 12 with 674.77 CDU/mg and 639.26 CDU/mg, respectively, under predetermined factors, in which the sodium alginate and calcium chloride solution concentrations were at 3.00% (w/v) and 0.30 M, respectively. The lowest actual and predicted proteolytic activities were at run 2 with the values of 77.35 CDU/mg and 71.53 CDU/mg, respectively, whereby factors include were a sodium alginate of 4.00% (w/v) and 0.20 M of calcium chloride solution. For the experimental feasibilities, the optimum conditions that was feasible to be carried out was with a sodium alginate of 2.99% (w/v) and 0.30 M calcium chloride solution. Verification for the optimum condition was performed and there was no significant difference (p > 0.05) between the predicted (638.19 CDU/mg) and verified (699.82 CDU/mg) values. Thus, indicating that the model was significant and can be used to produce the immobilize protease under the optimum condition.

Microplastic abundance in beach sediments of the Kiel Fjord, Western Baltic Sea

We assessed the abundance of microplastics (0.2–5 mm) in drift line sediments from three sites in Kiel Fjord, Western Baltic Sea. The first site is intensively used by beach visitors, the second is in close proximity to a sewage plant and the third is polluted with large-sized plastic litter. Samples were split into three grain size classes (0.2–0.5, 0.5–1, 1–5 mm), washed with calcium chloride solution, and filtered at 0.2 mm. Filters were then visually inspected, and a total of 180 fragments was classified as microplastics, of which 39% were analyzed using Raman spectroscopy. At the site that is close to a sewage plant as well as at the site with intense beach use, 1.8 and 4.5 particles (fibers plus fragments) per kg of dry sediment were found, respectively, while particle abundances reached 30.2 per kg of dry sediment at the site with high litter loads. Our data suggest that the fragmentation of large plastic debris at site seems to be a relevant source for microplastics in Western Baltic Sea beach sediments.

Effect of Calcium Chloride Hydrothermal Treatment of Titanium on Protein, Cellular, and Bacterial Adhesion Properties

Topographical modification of the dental implant surface is one of the main topics for the improvement of the material, however, the roughened surface has some risks for peri-implantitis. A hydrothermal treatment (HT) of titanium with calcium chloride solution was reported to improve osseointegration and soft tissue sealing without changing the surface topography; however, its mechanism is unclear. We herewith investigated the interaction between extracellular matrix (ECM) protein and HT titanium. Furthermore, we also clarified the bacterial interaction. We employed two kinds of HT, HT with water (DW-HT) and HT with calcium chloride solution (Ca-HT). As a result, the adsorptions of both laminin-332 and osteopontin onto the Ca-HT surface were enhanced. In contrast, the adsorption of albumin, which was reported to have no cell adhesion capacity, was not influenced by Ca-HT. Osteoblast adhesion onto Ca-HT was also enhanced. Although Ca-HT was reported to enhance both epithelial cell attachment strength and in vivo peri-implant epithelial bonding, the number of epithelial cell attachment was not increased even after HT. Ca-HT had no impact in the adhesion of Streptococcus gordonii. These results suggest that Ca-HT enhances cell adhesion onto titanium without increasing bacterial adhesion, and the improvement of ECM protein adsorption is supposed to contribute to cell adhesion.