Sorption of Cu, Zn, Pb and Cd from a Contaminated Aqueous Solution Using Starfish (Asterina pectinifera) Derived Biochar

Objectives : Heavy metal contamination and accumulation have a harmful effect on the health of humans and animals and are serious problems worldwide. Currently, various technologies have been used for the treatment of contaminated wastewater, of which adsorption is the most commonly known and economically feasible technology. Many researchers are making attempts to find an effective and easily available adsorbent in terms of cost. In this study, starfish (<i>Asterina pectinifera</i>, SF) derived biochar was prepared and its characteristics were evaluated through various device analyses. After the biochar evaluation, the adsorption capacity was evaluated by conducting batch experiments.Methods : Biochar (Pyrolyzed Starfish at 500℃, PSF500) was produced by pyrolysis at 500℃ for 2 h in anaerobic conditions. Moreover, the characteristics of the surface were evaluated through SEM, TGA, XRD, elemental analysis and FT-IR analysis. In addition, batch experiments using heavy metal contaminated wastewater were conducted.Result and Discussion : In PSF500, CaCO3, Ca(OH)2 and CaCO3 were identified as the main phases by XRD analyses and various functional groups and pores that affect adsorption were observed on the surface of the sample. The batch experiment confirmed that the maximum adsorption was 153.8, 270.3, 434.8, and 147.1 mg/g for Cu, Zn, Pb and Cd, respectively. Also, it was confirmed that all heavy metals fit the similar Pseudo-second-order kinetic model and Langmuir model, which are the most suitable models for analyses of inorganic pollutants. After the sorption experiment, XRD and SEM analyses were conducted using the residue of PSF500, and in each sample CuO, Zn5(CO3)2(OH)6, Pb3(OH)2(CO3)2, Cd(OH)2 and CdCO3 were confirmed to be deposited on the surface of the sample.Conclusions : It was confirmed that PSF500 follows the complex mechanism of adsorption and precipitation with respect to heavy metals. Based on the experimental results, PSF500 could be used as an eco-friendly sorbent with CaCO3 as its main ingredient.

Adsorption of Heavy Metals in an Aqueous Solution Using Starfish (Asterina Pectinifera) Biochar

Objectives:Heavy metals caused by industrialization have affected human society for several decades. Because of their toxicity for humans, lots of heavy metal treatments have been developed. However, many of those treatments have economic considerations and environmental disadvantages. This work explored an experimental assessment of adsorption of heavy metals using starfish (SF) biochar through quantitative and qualitative characterization and batch-tests.Methods:Biochar (NACSF) was produced at 300℃ for 2 h in anaerobic conditions. The NACSF was characterized with XRD, XRF, FT-IR, SEM-EDX and elemental analyses. Moreover, batch-tests for each heavy metal using NACSF were conducted with ICP-OES analyses in order to evaluate the adsorption characteristics.Results and Discussion:Based on the characterization results, the NACSF consisted of carbon and CaCO₃ mainly. The adsorption rates of Pb, Cu, Zn and Cd decreased in the following order: Pb≫Cu>Zn≥Cd. Moreover, the Langmuir equation fit all adsorption data better than the Freundlich equation. Also, due to the alkalinity of NACSF, the measured pH values of all experimental groups were approximately 7~8.Conclusions:The NACSF treatment was the most effective for Pb removal and it was determined that precipitation and surface adsorption were the most likely mechanisms for Pb removal. Thus, NACSF derived from starfish could be an cost-effective and eco-friendly treatment for heavy metal contaminated wastewater.

Effects of Polar Steroids from the Starfish Patiria (=Asterina) pectinifera in Combination with X-Ray Radiation on Colony Formation and Apoptosis Induction of Human Colorectal Carcinoma Cells

Despite significant advances in the understanding, prevention, and treatment of cancer, the disease continues to affect millions of people worldwide. Chemoradiation therapy is a rational approach that has already proven beneficial for several malignancies. However, the existence of toxicity to normal tissue is a serious limitation of this treatment modality. The aim of the present study is to investigate the ability of polar steroids from starfish Patiria (=Asterina) pectinifera to enhance the efficacy of radiation therapy in colorectal carcinoma cells. The cytotoxic activity of polar steroids and X-ray radiation against DLD-1, HCT 116, and HT-29 cells was determined by an MTS assay. The effect of compounds, X-ray, and their combination on colony formation was studied using the soft agar method. The molecular mechanism of the radiosensitizing activity of asterosaponin P1 was elucidated by western blotting and the DNA comet assay. Polar steroids inhibited colony formation in the tested cells, and to a greater extent in HT-29 cells. Asterosaponin P1 enhanced the efficacy of radiation and, as a result, reduced the number and size of the colonies of colorectal cancer cells. The radiosensitizing activity of asterosaponin P1 was realized by apoptosis induction through the regulation of anti- and pro-apoptotic protein expression followed by caspase activation and DNA degradation.