Adsorption Isotherm, Kinetic and Thermodynamic Studies of Nitrates and Nitrites onto Fish Scales

Abstract

AbstractOne of the most important things that every human being on the planet must be aware of is sustainability. The term ‘sustainability’ refers to all aspects of the environment, including numerous characteristics such as the long-term viability of water bodies. Water pollution has been rapidly increasing over the last two decades for a variety of reasons. The significant development of industries is beneficial to the country's economy. Even though the wastes generated by these various industries and disposed of without proper treatment and practises have caused and continue to pollute the water bodies. Nitrates are one of the pollutants that can be found in most polluted river bodies. Nitrates can be found in river bodies from agricultural waste water due to pollutants released primarily from fertilizers used in excess amounts for agricultural practises. Adsorption proved to be the best solution for controlling the nitrate content in water. In this study, nitrates and nitrites are removed from adsorbent fish scales. The removal of fish scales as an adsorbent has been thoroughly researched. These studies involve different isotherm studies, kinetic studies as well as thermodynamic studies. Following the completion of the analysis, the results revealed that nitrates and nitrates can be effectively removed with fish scales, with the maximum percent biosorption found to be 97.96 and 99.72% at contact times of 140 min and 100 min, respectively, the pH is kept at 6, the temperature is kept at 303 degrees Celsius, and the adsorbent dosage is kept at 0.4 g for maximum adsorption. Thermodynamic studies has been also conducted where the results showed that the reaction is endothermic and spontaneous in nature based on the values of ΔS, ΔH and ΔG. In addition to the above analysis, isothermal and kinetic studies were performed, with the Langmuir isotherm studies fitting perfectly and the affinity between the pollutants and adsorbent indicating that second-order kinetic studies are best suited.KeywordsAdsorbentKinetic studiesIsotherm studiesThermodynamic studiesFish scalesAdsorption