Examination of variables influencing photocatalytic membrane reactors by using textile industry wastewater brine via modeling

Abstract

Water scarcity has become a growing problem worldwide and is creating a serious crisis. Factors such as global warming, rapidly increasing population and mismanagement of water resources lead to rapid depletion of fresh water. This situation deeply affects not only people's daily lives, but also sectors such as agriculture and industry. Since water is the basic source of life, water scarcity poses a major threat both environmentally and economically. Various strategies need to be developed to cope with water scarcity. One of these strategies is the expansion of wastewater treatment. If wastewater is not treated properly, it pollutes the environment and further threatens water resources. However, today, thanks to modern purification technologies, dirty water can be made reusable. This not only saves water, but also contributes significantly to the protection of water resources. By making it possible to recycle water, wastewater treatment increases the sustainability of water supply, especially in regions where water scarcity is intense. At the same time, in places where access to clean water is limited, the use of purified water reduces health risks and improves quality of life. Dissemination of wastewater treatment technologies is of great importance for the efficient use and protection of water resources. In this context, proper management and purification of water plays a vital role for a sustainable life. The textile industry is an important economic sector both in Turkey and around the world. The processes used in textile production lead to significant amounts of water consumption and large amounts of wastewater are generated at the end of these processes. Wastewater produced in the textile industry generally pollutes the environment due to the dye, salt and chemicals it contains. However, it is possible to recycle this wastewater in some cases, and this recovery process enables wastewater to turn into an advantage. Since water usage is high in the textile industry, a large proportion of the world's wastewater originates from the textile industry. Wastewater characteristics of different industries vary depending on the production process of each sector. For example, the wastewater of the jeans industry and an industry producing coats are quite different in terms of the pollutants they contain. This difference makes wastewater treatment processes more complex and can reduce the effectiveness of treatment. In recent years, conventional wastewater treatment plants have experienced difficulties in treating various wastewaters coming from the textile industry. Therefore, more efficient purification techniques and advanced technologies are used. Advanced oxidation processes, membrane processes and advanced biological treatment processes are among the techniques with high removal efficiencies. The purpose of these processes is to remove pollutants in wastewater with high efficiency. Photocatalytic membrane reactors (PMR) consist of the combination of membranes and photocatalysis, one of the advanced oxidation processes, and have the ability to purify high pollutant concentrations in a short time. PMR is a very effective method for purifying pollutants such as dyes, especially those found in the wastewater of the textile industry. This technology causes the dye to degrade and is removed from wastewater. Moreover, the speed of the process can be increased by adding catalyst, making the PMR process more efficient and advantageous. The effectiveness of the PMR process depends on many different parameters. The most important among these parameters are factors such as catalyst concentration, light intensity and duration, and initial pollutant concentration. Correctly adjusting these factors can significantly increase the efficiency of the purification process. PMR has also been used in the medical field and effective results have been obtained in different applications such as drug removal. The use of this technology in the textile industry is an important step towards reducing environmental impacts and protecting water resources. In this thesis, it is aimed to remove dye from textile industry wastewater with PMR. A total of 5 different factors were considered in the PMR system and these factors were included in the model program. As a result of the model program, a total of 64 sets of operations were carried out and it was determined what effect was achieved on dye removal by using different catalyst concentrations by exposing wastewater of different concentrations to different durations and light intensities. The results of the tests performed on these sets include dye removal efficiencies, relative flux values of the membranes and operation-maintenance cost calculations. As a result of these analyses, optimum operating conditions that yield the most efficient results were determined. Then, by applying various processes to these optimum points, the accuracy of the model was tested and how the dye removal changed with different processes was checked. PMR systems are widely used, especially on a laboratory scale, but the number of studies with real wastewater is quite limited. Additionally, studies comparing the operating and maintenance costs of PMR sets are not often found in the literature. This study examining the performance of the PMR system depending on different factors and evaluating the results obtained in detail will make significant contributions to the literature. Additionally, using the wastewater of a jeans industry in Turkey and producing all of the membranes in Turkey provides an important opportunity for the study to encourage local production. In this way, while foreign dependency is reduced, all production, testing and interpretation stages are carried out locally. As a result, treating textile industry wastewater not only reduces environmental impacts, but also contributes to the protection of water resources and offers an important solution for sustainable water management. Advanced purification technologies such as PMR play a critical role in this process and emerge as an effective means of combating the problem of water scarcity in the future.