Recycling of waste printed first quality papers

With the developing technology and increasing population, it is important to meet the increasing paper / cardboard needs and to recycle waste paper for the sustainability of forests. The most important step for using 1st quality paper wastes as a raw material in recycled paper production is ink removal. In this study; in the recycling of printed 1st quality paper wastes, chemical, enzymatic and ultrasonic processes were used. Printed 1st quality paper wastes were pulped and ink was removed by flotation method using chemicals (NaOH and CaO) and enzymes (Amylase and Cellulase) at varying doses. Paper was then produced from these pulps. Four samples were produced to determine the effect of each dose on the recycled paper sample. The strength (tear strength, burst strength, tensile strength) and optical (CIE Whiteness, ISO Whiteness, ISO Brightness, Opacity) tests were performed. The results obtained were compared with the 1st quality paper values and the control sample values obtained by applying the same processes without any chemical/enzyme dosing. The whiteness values of the papers which were de-inked using NaOH and CaO remained below the 1st quality paper value but higher strength was observed. It has been shown that amylase enzyme provides superior success in deinking process and recycling paper quality. At a dose of 870 mg/L amylase, CIE Whiteness 147.78, ISO Whiteness 102.56, ISO Brightness 92.40, and Opacity 91.53 were obtained, and these values were found to be satisfying the 1st pulp - 1st quality paper whiteness values (145, 100, min.87 and min.86, respectively). It has been observed that the application of the enzyme together with chemical or ultrasonic treatment does not increase the success. It has been determined that the wastewater released as a result of the flotation process is of a nature requiring treatment. On the other hand, as a result of the property evaluation, it was determined that the pulp obtained after the removal of ink from the first quality paper waste by using the enzyme can be mixed with new cellulose in the production of first quality paper. Keywords: Deinking, Flotation, Enzyme, CIE whiteness, ISO whiteness, ISO brightness, Paper, Breaking strength, Bursting strength, Tear strength