Grass clippings may be turned into paper
Grass clippings from Universidad Nacional de Colombia (UNal) Palmira lawns were transformed into paper with textures similar to cardboard and pasteboard.Palmira, 11 de noviembre de 2015 — Agencia de Noticias UN-
Cardboard and pasteboard, product of a transformation process of Cynodon dactylon, Paspalum notatum flugge and Paspalum conjugatum grass clippings.
The team that developed paper from grass clippings. L to R: Professor Hugo Alexander Martínez Correa; undergraduate Jessica Joana Recalde Portilla; Professor Pedro Vanegas Mahecha and undergraduate Adriana del Rosario Micanquer Carlosama.
This as a Basic Engineering Processes and Unitary Operations Laboratory project (Process Engineering Practices course) in which 10 Agro-Industrial Engineering undergraduates choose to work on due to the ample and different campus lawns that are cut almost every day. “We also wanted to provide a use alternative for the grass clippings,” said Adriana del Rosario Micanquer Carlosama, member of the group.
The students had carried out a previous research project on the materials and the paper which could be obtained, “We chose the grass of the soccer field because we could use the waste and besides clippings were more uniform,” they added.
They identified three types of grasses with high cellulose and low lignin content: Cynodon dactylon, Paspalum notatum flugge and Paspalum conjugatum. Cellulose is the raw material used for making paper and fabric, as well as explosives and varnishes etc.; lignin is a non-usable material, therefore it is discarded.
According to the aforementioned, the amounts of cellulose and lignin made the grass clippings transformation project feasible, they were: 29.4% of cellulose for Cynodon dactylon, 5.9% for Paspalum notatum and 8.2% for Paspalum conjugatum; and values of 29.4%, between 24.5 and 33.8% and 30.5% respectively for lignin.
“Not all grass clippings are apt for producing paper; sugarcane bagasse is good for making writing paper and woody grasses are better for making cardboard,” said course Professor Hugo Alexánder Martínez Correa.
“Today we are looking on processing waste such as grass clippings to mitigate the impact of contaminating pasture burnings; therefore the students proposed this exploitation alternative”, said Pedro Vanegas Mahecha, Professor and part of a project entitled “Making paper from grass clippings (Cynodon dactylon, Paspalum notatum flugge and Paspalum conjugatum)”.
Another reason to carry out the project was to use less chemicals, such as sodium hypochlorite to transform paper waste, which contributes to mitigate impact from these productive processes on the environment,” said Micanquer.
“The project is technically viable and we demonstrated we could produce paper from this waste,” said Jessica Joana Recalde Portilla, another member of the group.
To obtain the paper, they first classified the clippings and then they dried the waste and de-lignified the product in order to obtain a cellulose paste through a cooking process in sodium hydroxide at 50° C (122° F) in marmites. They obtained a black substance which was the lignin which was then filtered to obtain cellulose paste, then they washed and bleached it with a sodium hypochlorite solution. Afterwards they used lignants to unite the cellulose particles and the cellulose was tinted pink, purple, blue and orange to observe the color absorption capability of the materials obtained. Then it was pressed and let to dry.(Por: Fin/HAA/MLA/CA