However,
application of such methods was sometimes restricted because of technical or economical constraints. It
has become a challenge for researchers to seek cheaper and more effective adsorbents for lead removal.
Tea is the most widely consumed beverage after water throughout the world for its beneficial effects on
health, such as antioxidant, anticarcinogenic, antimicrobial activities [4,5]. In China alone, the annual
production of tea was close to 135 million tons in 2009 and is increasing by 8.7% per year. During the tea
production procedure, high quality tea leaves are selected for the production of dried green tea or fermented
tea, while low quality tea leaves are used for the production of tea beverages and for the extraction of tea
polyphenol, caffeine, tea polysaccharide, etc. A great number of tea residues are produced for the production
of tea beverages and extraction, and usually discarded into the environment without any treatment, which
is not only a waste of resource, but also causes environmental hygiene problems during their degradation
process. Therefore, it is desirable to reuse these tea residues.