Chapters authored
Adsorption Isotherms: Enlightenment of the Phenomenon of Adsorption
Adsorption is a process in which a substance that is in a liquid phase accumulates on a solid surface and is then removed from the liquid phase. An adsorption isotherm describes the equilibrium of adsorption of a substance on a surface at a constant temperature. It represents the amount of material bound to the surface as a function of the material present in the solution. In the adsorption process, the compound to be removed is called the adsorbate and the solid on which the compound is adsorbed is called the adsorbent. The affinity of the adsorbate for the adsorbent is quantified using adsorption isotherms. Adsorption isotherms are mathematical equations that describe the relationship between the amount of adsorbate adsorbed on an adsorbent and the concentration of adsorbate in solution when equilibrium has been reached at constant temperature. Adsorption isotherms are performed by giving a volume-determined solution containing a known amount of adsorbate along with various dosages of the adsorbent. The mixture is held at constant temperature with stirring until it reaches equilibrium. When this is the case, the concentration of the adsorbate in the aqueous phase is measured and the adsorption capacity at equilibrium for each experiment is calculated from the mass balance.
Part of the book: Wastewater Treatment
A Fixed-Bed Column Sorption: Breakthrough Curves Modeling
Global attention has increasingly focused on environmental pollution due to its widespread and devastating impact. The urgency of addressing climate change has propelled it to the forefront of governmental agendas worldwide, emphasizing the need for actions to secure a pollution-free future. Pollution treatment methods have consequently gained global significance, with adsorption emerging as a particularly relevant approach, especially in developing economies. Adsorption proves to be a cost-effective, safe, efficient, and easily manageable method that can utilize low-cost or waste materials. In designing treatment systems based on adsorption, batch tests are crucial, employing adsorption isotherms such as Langmuir and Freundlich to understand the phenomenon. While equilibrium points are essential in some situations, continuous processes benefit from column implementations, where a fundamental understanding of breakthrough curves becomes pivotal. Various adsorption kinetic models, such as the Thomas model, Adams–Bohart model, Yoon–Nelson model, and bed-depth/service time (BDST) model, explain and determine breakthrough curves. The assessment of these models for compatibility with experimental data and model-generated data is essential. Criteria such as Mean Relative Error (MRE) and Normalized Relative Mean Square Error (NRMSE) are commonly employed to objectively select the most suitable model for a given scenario.
Part of the book: Sorption - New Perspectives and Applications [Working title]