SORPTION OF WATER

Sorption is a physical and chemical process by which one substance becomes attached to another.
Sorption includes both adsorption & absorption
e.g., liquids being absorbed by a solid or gases being absorbed by a liquid, cotton dipped in ink.
Sorption the process in which one substance takes up or holds another; adsorption or absorption
Sorption is a process in which a solute moves from a fluid to a particulate solid.
The food sorption isotherm describes the thermodynamic relationship between water activity and the equilibrium of the moisture content of a food product at constant temperature and pressure. ...
The typical shape of an isotherm reflects the way in which the water binds the system.

1. SORPTION OF WATER BY ASSIST. PROF. Dr. BERCIYAL GOLDA. P

2. CONTENTS Introduction Importance Sorption Isotherms Measurements of Sorption Isotherms Gravimetric Method Manometric Method Hygrometric Method

3. Sorption is a physical and chemical process by which one substance becomes attached to another. Sorption includes both adsorption & absorption e.g., liquids being absorbed by a solid or gases being absorbed by a liquid, cotton dipped in ink. Sorption the process in which one substance takes up or  holds  another; adsorption or  absorption Sorption is a process in which a  solute  moves from a  fluid  to a  particulate   solid . The food sorption isotherm describes the thermodynamic relationship between water activity and the equilibrium of the moisture content of a food product at constant temperature and pressure. ... The typical shape of an isotherm reflects the way in which the water binds the system. INTRODUCTION

4. The sorption of volatile liquids on materials such as paper toweling actually increases the volatility over that of the liquid itself. Adsorption and absorption are two types of sorption phenomena. Adsorption Adsorption is defined as the deposition of molecular species onto the surface. The molecular species that gets adsorbed on the surface is known as adsorbate and the surface on which adsorption occurs is known as adsorbent. Common examples of adsorbents are clay, silica gel, colloids, metals etc Absorption Absorption is a condition in which something takes in another substance. It is a physical or chemical phenomenon or process, in which atoms, molecules, or ions enter in the inner part (called "bulk") of a gas, liquid, or solid material. Definition Sorption is a physical and chemical process by which one substance becomes attached to another. Specific cases of sorption are treated in the following articles: Absorption 

5. Gravimetric analysis is a quantitative determination of the amount of analyte through a precipitation process, precipitate isolation, and determination of isolated product weight.  Gravimetry  = analytical methods that measure the mass or mass changes. Using an analytical balance

6. TYPES OF GRAVIMETRIC METHODS A. PRECIPITATION GRAVIMETRY Appearance of insoluble compounds in a solution containing our analyte when a precipitating reagent/precipitant is added. The precipitate is then: filtered and washed (impurities removal) converted to a product (known composition) weighed. A gravimetric method in which the signal is the mass of a precipitate is called precipitation gravimetry .

7. B. Electrogravimetry A gravimetric method in which the signal is the mass of an electrodeposit on the cathode or anode in an electrochemical cell. Aqueous ion: determination of Pb2+ by oxidizes to PbO2 and deposited on Pt anode (chemical converting)

8. C. Volatilization gravimetry A gravimetric method in which the loss of a volatile species gives rise to the signal (remove the volatile species) Moisture: determination of water in food content by heat or thermal or chemical energy (heating)

9. D. Particulate gravimetry A gravimetric method in which the mass of a particulate analyte is determined following its separation from its matrix Suspended solid: determination of solid that can be separated from the sample (filtration or extraction)

10. STEPS IN GRAVIMETRIC ANALYSIS Gravimetric Analysis Dissolve a sample after weighing. A precipitating agent with excess amount is added to this solution. The resulting precipitate is filtered, dried (or ignited) and weighed. 4. Determine the amount of the original ion from the mass of the precipitate (known composition). 5. Stoichiometry is important (write down the chemical equation!). Sample dissolution Precipitation Digestion Filtration & washing of precipitate Drying of precipitate Weighing of precipitate Data calculations

11. Manometry technique of measuring the pressure variation due to gas production/consumption caused by biochemical reactions or physical changes Applicable to any bioprocess implying the production/consumption of a poorly soluble gas. Main applications: aerobic processes (oxygen consumption) anoxic processes (N2 production) anaerobic processes (biogas production)

12. Hygrometric methods are based on equilibrium relative humidity (ERH) instead of moisture content. ERH is numerically equal to water activity but expressed as a percentage of the actual amount of water in the air versus the amount of water the air could hold at saturation  A hygrometer is an instrument used to measure the amount of water vapor in air, in soil, or in confined spaces. Humidity measurement instruments usually rely on measurements of some other quantities such as temperature, pressure, mass, a mechanical or electrical change in a substance as moisture is absorbed. By calibration and calculation, these measured quantities can lead to a measurement of humidity. 

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