جستجوی مقالات مرتبط با کلیدواژه « ریزجلبک » در نشریات گروه « عمران »

Microalgae have the potential to produce valuable substances for pharmaceutical purposes as well as serve as a food source, providing bioactive compounds and ingredients for cosmetics. However, harvesting microalgae is a crucial step in the mass production of various high-value products derived from microalgae. This process often becomes a major bottleneck in downstream processing. It is essential to find effective and cost-effective harvesting methods for industrial applications. Among several harvesting methods, magnetic flocculation offers the benefits of modest operation, energy savings, and quick separation. This study investigates the harvesting process of Chlorella sorokiniana pa.91 microalgae using a novel flocculation process involving nano-Fe3O4 coated with PACl. In this research, we have used the chemical co-precipitation method to prepare nanoparticles. Using the response surface method to optimize the most important parameters of the magnetic flocculation harvesting process to check the microalgae removal efficiency, three variables of time, concentration of nanomaterials, and pH in the culture medium obtained from municipal wastewater have been investigated. The results demonstrated that the highest harvesting efficiency, nearly 90%, was achieved under the conditions of 3.5 g/L Fe3O4, a constant concentration of 0.075 g/L PACl, a harvesting duration of 40 minutes, and a pH level of 4. On the other hand, the lowest microalgae harvesting efficiency was observed under specific conditions: a composite nanoparticle concentration of 0.5 g/L per liter, a harvesting time of 27.5 minutes, and a pH of 6.5 resulting in a mere 22% efficiency. The rate of microalgal removal increased from 53% in the most alkaline condition to 75% in the most acidic environment. The highest harvesting efficiency, reaching 80%, was achieved under neutral pH conditions with a settling time of 53 minutes. Furthermore, the investigated combined method investigated enhances the flocculation effectiveness of microalgae. Based on the findings, it can be inferred that the efficiency of microalgae harvesting rises with longer duration, higher nanoparticle concentrations, and lower pH levels

Industrialization and growth of population during the last century has led to destruction of many ecosystems used by mankind. Entrance of different kinds of sewage to open water and rivers is known as the first factor reducing the quality of water resource available for mankind. The volume of pollutants in the sewage including total suspended solid, biological oxygen demand and chemical oxygen demand, reached tens of thousands milligrams per liter (Chan et al., 2009).Generally, in order to achieve sustainable economic development, water resources and wastewater management are necessary. Hence, it is necessary to use cost effective methods beside practical methods. Using microalgae for treatment of different kinds of municipal, agricultural and industrial wastewater is an affordable method (de Godos et al., 2010; Di Termini et al., 2011; Muñoz and Guieysse, 2006). Nowadays using microalgae in wastewater treatment has gained lots of attention, since microalgae can produce large amounts of biomass in order to attain valuable products and energy besides wastewater treatment and also prevent carbon dioxide from entering the atmosphere. Furthermore, treatment of different kinds of wastewater by means of microalgae is an environmental friendly method, because in this process no secondary pollutant is produced. The produced biomass is also recycled and used (Olguin, 2003; Rawat et al., 2011).