Separation of medicinal catechins from tea leaves (Camellia sinensis) extract using hollow fiber supported liquid membrane (HF-SLM) module

Catechins have been recovered in medicinal grade ethanol from tea leaves through hollow fiber supported liquid membrane (HF-SLM) module. In the first phase, synthetic solution of single catechin compound has been used for experimentation to optimize operating conditions. The tests with real extract of green tea leaves followed in the second phase with the similar operating conditions as optimized in the first phase. Tributyl phosphate (or TBP) as a carrier component dissolved in solvent n-decane was used as liquid membrane (LM). Ethanol was found to be ideal strippant of catechins. The flow rates of feed/strip streams and differential pressures across the membrane surfaces were optimized for achieving a stable liquid membrane. The established models for the solute transportation in LM, as found in various literatures, were revisited to explain the experimental results. Preliminary suggestions for the once-through transportation of catechins have also been provided for possible application in a pilot-plant.