1 HA NOI UNIVERSITY OF SCIENCE AND TECHNOLOGY SCHOOL OF CHEMICAL ENGINEERING DEPARTMENT OF PHARMACEUTICAL CHEMISTRY AND PESTICIDES TECHNOLOGY ACADEMIC ESSAY EXTRACTION TECHNIQUES Instructor: Dr. Dinh Thi Phuong Anh Student: Ngo Thi Thuy Student ID: 20175228 HÀ NỘI. Solid-liquid extraction ( ionic liquid) .2 Solid- liquid Extraction Process .1Principle of Solid – Liquid Extraction.2 Solid- liquid Extraction Process. Solid-Liquid Extraction Equipment.Applications of Solid-Liquid Extraction(Ionic-liquid).
Microwave-assisted extraction .2 Principles of Microwave-Assisted Extraction.3 Microwave extraction process .4 Microwave Assisted Extraction equipment .Application of MAE. Principles of Pertraction. Process of perstraction.Specific advantages and disadvantages. Applications of Perstraction.
Solid-liquid extraction 1.1 Denifintion ➢ Solid-Liquid Extraction is a solid-liquid contact mass transfer operation in which solute particles are transferred from solid to liquid. ➢ Solid-liquid extraction is also called Leaching. ➢ Solid-liquid extraction works on the principle of difference in solubility of specified solids in liquids. ➢ The liquid used for solid-liquid extraction is called the solvent.
The Solid which carries solute particles is called an insoluble solid.1 Ionic liquids (ILs) Ionic liquids (ILs) are widely recognized solvents due to their extended list of excellent properties, and their success comesmainly fromtheir unique and fascinating characteristics as non-molecular solvents, a negligible vapor pressure associated to a high thermal stability, tunable viscosity and miscibility with water and organic solvents. These properties are the result of being molten salts that are liquid below 100 ◦C which generally consist of organic cation (e. imidazolium, pyrrolidinium, pyridinium, tetraalkyl ammonium or tetraalkyl phosphonium) and inorganic or organic anion (e. tetrafluoroborate, hexafluorophosphate, bromide).
In addition, the high number of possible combination provides a long list of ILs with different polarity, hydrophobicity and viscosity, among others. For this reason ILs are known as “designer solvents” 6 Table 1. The structures of the ILs applied in extraction and separation: 7 8 1.2 Solid- liquid Extraction Process 1.1 Principle of Solid – Liquid Extraction Solid-Liquid Extraction occurs in two steps: • Contacting solvent and solid to effect a transfer of a solute (leaching) • The separation of the solution from the remaining solid (washing) ❖ Factors Affect Solid-Liquid Extraction Operation 1. Solid: Solid used for solid-liquid extraction can be porous or nonporous.
The solute may be distributed on a solid surface or inside pores of solid. Recovery of solute from the solid surface is easier than from pores of solid. Pores of solid create another mass transfer resistance for the solvent to go in and for the solute to come out. Solid particle's size also plays an important role in the operation.
Recovery of solute from small size solid particles are easier and more effective than bigger particle sizes. Solvent: The solvent used for operation is also an important parameter to take into consideration in operation. The solvent which contains desirable properties which are listed below is more preferred. Temperature: Temperature is also an important parameter in solid-liquid extraction because the solubility of solid particles is also dependent on temperature.
Mixing: Mixing of solid particles and liquid solvent decides the effectiveness of contact which is also important for parameter solid-liquid extraction. More thorough mixing confirms more contact between solid and liquid and this results in higher mass transfer.2 Solid- liquid Extraction Process ➢ Solid-liquid extraction there are steps 1. Size reduction of solids 2. Mixing of solids with solvent Liquid 3.
Overflow and underflow separation 4. Solvent recovery from overflow and underflow 9 ➢ Solid-liquid phase extraction is achieved through the interaction of three components: • the sorbent • the analyte • the solvent. ➢ Type of ionlic liquid extraction This section is thus divided into three parts based on the most frequently employed extraction processes: ➢ simple IL-based SLE; ➢ IL-based MAE; ➢ IL-based UAE.Solid-Liquid Extraction Equipment 1.1 Soxhlet Extractor The Soxhlet extractor is used for liquid-solid extractions when the compound to be extracted has limited solubility in the chosen solvent and the impurities are insoluble. During the extraction, solvent vapour will flow up the distillation path, into the main chamber and up into the condenser where it will condense and drip down.
The solvent will fill the main chamber, dissolving some of the desired compound from the solid sample. Once the chamber is almost full, it is emptied by the siphon, returning the solvent to the round bottom flask to begin the process again. Each time the extraction is repeated, more of the desired compound is dissolved, leaving the insoluble impurities in the thimble. This is how a compound is removed from the sample.
10 ➢ The Soxhlet extractor will run continuously once set up correctly: ➢ Load the sample material containing the desired compound into the thimble ➢ Place the thimble into the main chamber of the Soxhlet extractor ➢ Add the chosen solvent to a round bottom flask and place onto a heating mantle ➢ Attach the Soxhlet extractor above the round bottom flask ➢ Attach a reflux condenser above the extractor, with cold water entering at the bottom and exiting above ➢ Now the apparatus is set up, heat the solvent to reflux and leave to extract for the required amount of time 11 1.2 Bollman extractor This type of extractor, widely used for the extraction of vegetable oils from seeds, consists of a number of baskets fixed to an endless chain having a descending and an ascending leg, enclosed in a vapour tight chamber. Each basket has a perforated bottom (wire-mesh). There are two sumps hold the extract streams. Liquids percolating through the baskets along the two legs flow down to these sumps.
The solid is fed through a hopper into the basket at the top of the descending leg and partially enriched extract (50% extract) is sprayed on the solid. The liquid percolates through the slowly moving basket and collects at one of the bottom sumps of the unit. Fresh extractant is sprayed on the top basket in the ascending leg and percolates through the rising basket and collects in the other sump at the bottom in the form of 50% extract, which is sprayed on the top basket of the 12 ascending leg. Percolation of the liquid occurs counter-current in the descending leg and co-current in the ascending leg.
An extractor of this type may be 15 – 20 meters high. At the top of the tower, the baskets are tipped into a hopper, which is provided with a screw conveyor at its bottom to discharge the spent solids. This process has the following advantages and disadvantages : Advantage: 1. Can be integrated into continuous process 2.
Extraction efficiency is high 3. Final extract is fairly concentrated Disadvantages: 1. Cost of equipment is high 2. Large equipment, so maintaining stable optimal thermal profile is difficult 3.
Hydraulic conductivity of soaked leaves is low and it impairs percolation. Sometimes chanelling through leaf matrix also occurs which also have adverse effect on extraction efficiency.3 Hildebrandt Extractor This type of extractor is being used nowadays in a wide scale for extraction of different natural products. In this system the solid is immersed in the extractant. The system comprises of two long sections of tubes fitted with screw conveyors inside.
A feed hopper is provided in one end of the horizontal section and the solid is loaded into the tube through this hopper. Then the solid is transported to the other end be the slow moving screw conveyor. At the other end of the tube there is another section of tube which forms an angle with the first tube. There is a solvent entry port at around middle of the second tube, through which the extractant is pumped in.
The solid meets the extractant in countercurrent manner when it is transported through the horizontal tube and in first part of the upward angled tube. The solid is then carried upward in the second half of the upward angle tube, where it is drained and the drained solid is ultimately discharged from the extreme end of the upward angled tube. The extract flows out through an outlet port at the extreme end of the horizontal section. The entire unit can be steam jackated for precision temperature control.
Precision process control 14 2. Extraction is through immersion method, so hydraulic conductivity is not an issue in extraction stage 3. High thermal efficiency 4. High concentration of the product in the extract due to countercurrent extraction ➢ Disadvantages 1.
Hydraulic conductivity may be an issue in the draining stage 2. Precision mechanical parts need high maintenance 15 1.Bonotto Extractor the solids during their passage through the unit. The design offers the obvious advantages of countercurrent action and continuous solids compaction, but there are possibilities of some solvent loss and feed overflow, and successful operation is limited to light, permeable solids. 16 A somewhat similar but simpler design uses a horizontal screw section for leaching and a second screw in an inclined section for washing, draining, and discharging the extracted solids.
In the De Danske Sukkerfabriker, the axis of the extractor is tilted to about 10° from the horizontal, eliminating the necessity of two screws at different angles of inclination. Sugar-beet cossettes are successfully extracted while being transported upward in a vertical tower by an arrangement of inclined plates or wings attached to an axial shaft. The action is assisted by staggered guide plates on the tower wall. The shell is filled with water that passes downward as the beets travel upward.
This configuration is employed in the BMA diffusion tower (Wakeman, loc.) reports that screw-conveyor extractors, once widely employed to extract flaked oil seeds, have fallen into disuse for this application because of their destructive action on the fragile seed flakes. Tray Classifier A hybrid like the screw-conveyor classifier, the tray classifier rakes pulp up the sloping bottom of a tank while solvent flows in the opposite direction. The solvent is forced by a baffle to the bottom of the tank at the lower end before it overflows. The solids must be rugged enough to stand the stress of raking.Kennedy extraction 17 interial into or from the interior of the solid particles rather than the rate of transfer to or from the surface of particles, the main function of the agitator is to supply unexhausted solvent to the particles while they reside in the tank long enough for the diffusive process to be completed.
The agitator does this most efficiently if it just gently circulates the solids across the tank bottom or barely suspends them above the bottom. The leached solids must be separated from the extract by settling and decantation or by external filters, centrifuges, or thickeners, all of which are treated elsewhere in Sec. The difficulty of solids-extract separation and the fact that a batch stirred tank provides only a single equilibrium stage are its major disadvantages. Pachuca Tanks Ores of gold, uranium, and other metals are commonly batch- leached in large air-agitated vessels known as Pachuca tanks.
A typical tank is a vertical cylinder with a conical bottom section usually with a 60° included angle, 7 m (23 ft) in diameter and 14 m (46 ft) in overall height. In some designs air is admitted from an open pipe in the bottom of the cone and rises freely through the tank; more commonly, however, it enters through a central vertical tube, characteristically about 46 cm (18 in) in diameter, that extends from the bottom of the tank to a level above the conical section—in some cases, almost to the liquid surface. Before it disengages at the liquid surface, the air induces in and above the axial tube substantial flow of pulp, which then finds its way down the outer part of the tank, eventually reentering the riser.Applications of Solid-Liquid Extraction(Ionic-liquid) The use of IL-based SLE techniques with pure ILs, as well as with their aqueous solutions and IL-methanol/ethanol mixtures, for the extraction and separation of natural compounds, namely alkaloids, terpenoids, flavonoids, phenolics, saponins, lignans, among others: ➢ The use of IL aqueous solutions on the SLE of • alkaloids (e., glaucine from Glausium flavum).
