To increase the purity level of a chemical from 80% to 99%, several purification techniques can be employed in chemical engineering. The choice of method depends on the specific chemical, its properties, and the impurities present. Here are some common purification techniques:1. Distillation: This method involves heating a mixture to create vapor, then cooling the vapor to separate the components based on their boiling points. This technique is suitable for chemicals with significantly different boiling points compared to their impurities.2. Crystallization: In this process, the chemical is dissolved in a solvent, and then the solution is cooled or evaporated to form crystals. The impurities remain in the solvent, and the purified crystals can be separated through filtration. This method is suitable for chemicals with a high degree of solubility in a specific solvent.3. Chromatography: This technique separates components of a mixture based on their affinity for a stationary phase such as a solid or liquid and a mobile phase such as a liquid or gas . The components with a higher affinity for the stationary phase move more slowly, allowing for separation. Chromatography can be used for a wide range of chemicals and is particularly useful for separating complex mixtures.4. Extraction: This method involves using a solvent to selectively dissolve the desired chemical, leaving the impurities behind. The solvent is then evaporated or separated, leaving the purified chemical. Extraction is suitable for chemicals with a high degree of solubility in a specific solvent and low solubility in the original mixture.5. Membrane separation: This technique uses a semi-permeable membrane to separate components based on their size, charge, or other properties. The desired chemical passes through the membrane, while the impurities are retained. Membrane separation is suitable for chemicals with specific properties that allow them to pass through the membrane while impurities are retained.6. Adsorption: In this process, the desired chemical is selectively adsorbed onto a solid surface, while the impurities remain in the solution. The adsorbed chemical can then be desorbed and collected. Adsorption is suitable for chemicals with a high affinity for a specific adsorbent material.To develop a purification process, it is essential to understand the properties of the chemical and the impurities, and then select the most appropriate technique or combination of techniques. The process may require optimization to achieve the desired 99% purity level, which can be done through experimentation and process modeling.