According to chemist Jennifer Tamayo, of the DOST’s Forest Products Research and Development Institute (FPRDI) in Los Baños, Laguna, she found out that tree barks could trap ions of lead and chromium present in the wastewater of steel galvanizing plants.
Lead and chromium pose health hazards because they cause biological mutation and kidney and liver cancer, respectively.
In a statement, Tamayo said tree barks, which are considered waste in industrial tree plantations, "have tannins, lignins, organic acid and cellulose that can absorb or trap heavy metals in a solution."
Tamayo added that tree barks "have the potential to substitute for costly synthetic adsorbents presently imported by the wastewater treatment industry at about $8 million a year."
Her experiment showed that waste barks could remove 96 to 100 percent lead and 84 to 90 percent chromium from wastewater.
She made the discovery while pursuing a Masters of Science in Chemistry Education at the University of the Philippines in Los Baños under the guidance of Dr. Maxima Flavier.
Dr. Florence Soriano, FPRDI director, said the "technology, once adopted, could help make industries better able to comply with present and future environmental laws."
Tamayo’s study covered mangium (acacia manguim), bagras (eucalyptus deglupta), river red gum (eucalyptus camaldulensis), moluccan sau (paraserianthes falcataria), gubas (endospermum peltatum), kaatoan bangkal (anthocephalus chinesis), rainfree (samanea saman) and yemane (gmelina abrorea).
The Philippines produces a lot of waste barks from about 653,000 hectares of industrial tree plantations established by both government and private groups.
"Barks make up 10 to 20 percent of the trunk’s total volume, which remain an untapped source," Tamayo said.
Among the tree species studied, gubas and river red gum showed the best results because their barks removed the most ions and did not impart color in the solution.