RESUMEN
This study examined the ability of the green microalgae Chlorella vulgaris to remove arsenic from aqueous solutions. A series of studies was conducted to determine the optimal conditions for biological arsenic elimination, including biomass amount, incubation time, initial arsenic level, and pH values. At 76 min, pH 6, 50 mgL-1 metal concentration, and 1 gL-1 bio-adsorbent dosage, the maximum removal of arsenic from an aqueous solution was 93%. The uptake of As (III) ions by C. vulgaris reached an equilibrium at 76 min of bio-adsorption. The maximum adsorptive rate of arsenic (III) by C. vulgaris was 55 mg/gm. The Langmuir, Freundlich, and Dubinin-Radushkevich equations were used to fit the experimental data. The best theoretical isotherm of Langmuir, Freundlich, or/and Dubinin-Radushkevich for arsenic bio-adsorption by Chlorella vulgaris was determined. To choose the best theoretical isotherm, the coefficient of correlation was used. The data on absorption appeared to be linearly consistent with the Langmuir (qmax = 45 mgg-1; R2 = 0.9894), Freundlich (kf = 1.44; R2 = 0.7227), and Dubinin-Radushkevich (qD-R = 8.7 mg/g; R2 = 0.951) isotherms. The Langmuir and Dubinin-Radushkevich isotherms were both good two-parameter isotherms. In general, Langmuir was demonstrated to be the most accurate model for As (III) bio-adsorption on the bio-adsorbent. Maximum bio-adsorption values and a good correlation coefficient were observed for the first-order kinetic model, indicating that it was the best fitting model and significant in describing the arsenic (III) adsorption process. SEM micrographs of treated and untreated algal cells revealed that ions adsorbed on the algal cell's surface. A Fourier-transform infrared spectrophotometer (FTIR) was used to analyze the functional groups in algal cells, such as the carboxyl group, hydroxyl, amines, and amides, which aided in the bio-adsorption process. Thus, C. vulgaris has great potential and can be found in eco-friendly biomaterials capable of adsorbing arsenic contaminants from water sources.
RESUMEN
This study is intended to evaluate the cytotoxicity of native and dual-modified black rice flour against the colon cancer cell line (HCT116) and mouse embryo cell line (3T3-L1) by using the MTT assay. The modification techniques applied to prepare rice flour samples were enzymatic modification and heat moisture treatment. In this study, the IC50 of native black rice flour and modified black rice flour was 255.78 µg/mL and 340.85 µg/mL, respectively. The result confirms that the native black rice flour has significant cytotoxic and anticancer potential against human colon cancer cells. In addition, the IC50 of native black rice flour and modified black rice flour on the 3T3-L1 cell line was found to be 345.96 µg/mL and 1106.94 µg/mL, respectively. The results showed that the native black rice flour had weak cytotoxicity, and modified black rice flour was nontoxic in both the cell lines. The active component of phytochemicals present in black rice flour has a potential role in preventing colon cancer.
RESUMEN
The present study aimed to descry the effectiveness of dried microalga Chlamydomonas sp. for disposing of arsenic from aqueous solution. The study included examining the impact of some factors on algae's adsorption capacity (optimization study), such as initial concentrations of heavy metal, biosorbent doses, pH and contact time. All trials have been performed at constant temperature 25 °C and shaking speed of 300 rpm. The optimization studying indicated the pH 4, contact time at 60 min, temperature 25 °C and biomass concentration of 0.6 g/l were the best optimum conditions for the bioremediation activity with maximum removal percentage 95.2% and biosorption capacity 53.8 mg/g. Attesting of biosorption by applying FTIR (Fourier transfigure infrared), XRD (X-ray diffraction), SEM-EDX (Scanning Electron Microscope - Energy Dispersive X-ray), DLS (Dynamic light scarring) and ZP (Zeta Potential) was conducted. Also, Kinetics, isotherm equilibrium and thermodynamics were carried out to explain the plausible maximum biosorption capacity and biosorption rate of biosorbent q maximum.
RESUMEN
Microalgae sorbents are microalgae that have the potential to passively bind heavy metals/contaminants to their cellular structures in a process called biosorption. This study investigates the use of two species of microalgae to remove the toxic heavy metal cobalt from aqueous solution. Two microalgae isolates, Phormidium tenue and Chlorella vulgaris, were collected from the Wadi Hanifah Stream in Riyadh, the Kingdom of Saudi Arabia. We determined the capacity of both isolates to bioremove Co+2 ions and the optimum conditions under which this occurs. The two isolates were additionally characterized by microscopic and Fourier transform infrared spectroscopy (FTIR). In the current investigation, Phormidium tenue removed 94% of Co+2 under ideal conditions of pH 6, contact duration (30 min), starting concentration (50 mgL-1) and biosorbent dose (1gL-1); while Chlorella vulgaris removed 87% of Co+2 under the same parameters except pH 5.5 and contact duration (60 min). Fourier transform infrared spectroscopy (FTIR) confirms the binding of Co+2 to the biomass, which comprises many of the functional groups. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) showed some alterations to the shape of algal cells and cellular components for both microalgae studied. In addition, equilibrium study by both Langmuir and Freundlich models was performed to detect the effect of certain equilibrium factors on the capacity of the biosorption mechanism. Finally, Phormidium tenue and Chlorella vulgaris were discovered to be promising microalgae for effective cobalt biosorption in aquatic conditions.
