Environmental friendly technology to remove ink stain in paper recycling
The
greatest challenge in paper recycling is removal of polymeric ink and
coating; and the most difficult paper is mixed office
wastepaper.Traditional deinking processes involve large quantities of
chemicals which are expensive and unfriendly to the environment. A
better alternative would be a technology that involves biological
intervention.
The greatest challenge in paper recycling is
removal of polymeric ink and coating. It was suggested that the most
difficult raw material for deinking is the mixed office wastepaper
especially the papers that had gone through photocopiers and laser
printers.
Traditional deinking processes involve the use of
large quantities of chemicals. Not only is this expensive, it causes
pollution to the environment due to the excessive use of chemicals.
Environmental friendly technology that exploits enzymes (biological
molecules) potential has been the focus of many researches that look
for lower operational cost and minimal environmental impact in paper
deinking processes.
Enzymatic treatment can achieve similar
effect as chemical treatment. It can even improve the deinking results
without affecting the physical properties in the final paper product.
Application of enzyme stable in alkaline environment has been shown in
other research to be effective in increasing the brightness and reduced
the ink counts of recycled paper.
A research project conducted
by Universiti Malaysia Sarawak and Sarawak Forestry Corporation
reported the use of a crude enzyme preparation for the enzymatic
deinking of mixed office paper. The enzyme material was prepared by
growing endoglucanase (enzyme use for the enzymatic treatment)
producing Bacillus licheniformis BL-P7 in a liquid culture media
containing sago pith waste and rice husk.
The enzymatic effect
was compared to the conventional chemical treatment. The enzymatic
deinking process was reported to produce better deinking effects on the
mixed office paper compared to conventional chemical methods. Ink
detachment from the paper fibre was facilitated by the enzymatic
modification of the fibre surfaces. Furthermore, the process proved to
be more effective for the removal of larger ink particles. Also,
properties such as brightness, air permeability, tensile, and tear were
enhanced in the handsheets preparation of the recycled mixed office
paper.