The effect of glanapone organic complex on the Properties of ONP Deinked Pulp

Background and objectives: Today, paper recycling is considered as a very important economic and environmental necessity. Deinking is one of the important processes in paper recycling. Different types of chemicals are used for deinking that one of the most important of them is sodium silicate. Silicate compounds reduce the useful life of processing equipments and cause problems in the wastewater treatment system due to the sedimentation of them in the equipment. In this research, Recycling of old newspaper using glanapon organic complex, as a substitute for sodium silicate, was investigated due to related problems with sodium silicate.
Materials and methods: In this study, chemical repulping of ONP was carried out using chemicals at pulp consistency of 10%, temperature of 50 °C and duration of 20 min. The chemicals used for deinking were hydrogen peroxide, sodium hydroxide, Surfactant (Tween 80), DTPA, and glanapon stab organic complex. All chemicals were added based on oven-dry paper basis. In the first step, the control pulp was prepared from ONP using 1% sodium hydroxide, 1% hydrogen peroxide, 0.15% Surfactant (Tween 80) and 0.3% DTPA in the presence of 0.5% sodium silicate. Then, in subsequent treatments, sodium silicate was removed from the chemical compound and the glanapone complex was used at various levels (0.3, 0.5, 0.7, 1, 2 and 3%) instead of it. All chemical treatments were carried out in plastic bags in a hot water bath. The treated pulps were deinked by washing method. The effect of various charges of glanapone on the formation of hydrogen bonds was investigated by infrared spectroscopy (ATR-FTIR). The effect of various charges of the organic complex on the physical, optical and strength properties of deinked pulp was studied and compared with the control (ONP deinked using 0.5% sodium silicate).
Results: The results of physical properties measurements showed that the addition of glanapon stab complex up to 0.7% level caused to production of papers with lower caliper and higher density. Microscopic images taken from the thick profiles of the papers also confirm this. As well as, Paper thickness increased and their density was decreased by increasing consumption of glanapon from 0.7 to 2%. While the density of the prepared paper increased as compared to the reference paper. The results of optical properties analysis indicated that the brightness increased to 51.21% ISO and the yellowness was reduced to 7.3 % ISO as the dosage of organic complex was increased up to 3%. The opacity of paper was decreased by increasing the organic complex charge up to 0.7%. The bursting strength was significantly increased by increasing the organic complex charge up to 2% as compared to the reference paper.
Conclusion: In general, the paper with lower caliper, higher density and brightness, lower yellowness and suitable opacity could be produced using 0.3- 2% glanapon complex in comparison with the reference paper by deinking of old newspaper