The Chemistry of Recycling Paper

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With talks of global warming, more healthcare benefits, and the crusade for preserving the Earth, attention has been focused on the campaign for recycling.  According to the Environmental Protection Agency (EPA), recycling prevents pollution caused by the manufacturing of products from virgin materials, recycling conserves natural resources such as timber, water, and minerals, while recycling decreases emissions of greenhouse gases that contribute to the global climate change, thus, helping to sustain the environment for future generations.   As ironic as it seems, in order to achieve the eco-friendly final process of recycling paper, unfriendly environmental chemicals must be used, sometimes emitting byproducts that are not suitable for human contact.  How aware are we about the chemicals used for recycling paper? 

With productivity being the theme of any type of work, many do not stop and think about what chemicals go into making recycled paper. One of the great advantages to recycled paper is less usage of chemicals, preventing less pollution caused by products from virgin materials.  After the collection process begins (recycled bins, drop-off centers, buy-back centers, etc.), immediately there is the pulping stage, sometimes called the de-inking stage, which dissolves and rips the ink from previously printed paper materials like newspapers and magazines. 

Depending on the paper processing plant, a chemical that is used during the pulping process is chlorine dioxide.  According to the article, “How Well Do You Know Recycled Paper”, chlorine dioxide produces the carcinogen dioxin.  Since the EPA has been the governing body to ensure processing plants are compliant in regards to being environmentally safe and the emission of waste products, there is a process that is chlorine free, which meets the EPA’s 30 percent minimum requirement for recycled/post consumer waste content.  This allows for the non-chlorine alternative of using oxygen, hydrogen peroxide, and enzymes.  Stephenson Recycling Chemicals (SRC) is one of the world’s leaders in deinking chemicals, according to their website.  The website boasts about how the company manufactures a patented blend of anionic surface agents with compounded enzymes, like the T3000EP.  Enzymes like the T3000EP are designed for enhanced ink removal by detaching the ink at the paper fiber. 

Often consumers may find themselves purchasing paper that may not be 100 percent recycled.  In this situation, there is a great chance that virgin materials have been used, which also means, there is a more than likely chance that harsher chemicals were used in the process of pulping the virgin materials.  The Kraft process is an alkaline process, which means instead of using acid compounds to assist with pulping, more compounds like hydroxides (OH) are used.   The lignin in wood is cracked by sodium hydroxide (NAOH) or sodium sulfide (NA2S), which is very effective in breaking down different kinds of woods, especially if the wood contains pollutants.  

The two chemicals are effective in getting the job done, but are highly corrosive chemicals which can cause severe burns on the mucous membranes, along with the disadvantage of carrying an odor, and producing the byproduct of thiols and sulfides.  Due to the odor, this means that now the pulp has to be bleached more.  As more chemicals may be added to continue giving the paper a whiter color, like calcium carbonate (CaCO3), talc, or titanium dioxide (TiO2), other chemicals are added to make the processing simpler like starch, latex, or aluminum sulfate (Al2(SO4)3). 

Consumer concerns have been steady in regards to the effects these various chemicals may have on humans and everyday contact with products made of recycled paper.  Since cardboard is being used as a recycled product now, studies have been performed to research how similar the recycling process is for both cardboard and paper.  Studies have proven that there is no difference in the processes for both, which raises questions from consumers.  In an article from Science Daily, “Chemicals From Recycled Cardboard May Contaminate Take-out Food, Researchers Say”, the article talks about the unhealthy facts of recycling paper and how these products are being used to house and transport foods.  “If the original paper is loaded with inks, adhesives and other substances, then these will be passed into the new recycled material. If that material is used to package food then the food could be exposed to the chemicals from recycling. One chemical of particular concern is diisobutyl phthalate (DIBP). This is commonly found in inks and other chemicals used in printing. It is potentially dangerous because it has a similar structure to androgenic hormones in the human body.”

As much as people feel that it is our current responsibility to preserve the natural resources of the planet like trees, plants, water, and other things that are generally overlooked and taken for granted, it is also a personal responsiblity to maintain health and promote less aggressive methods of production and recycling resources that will be needed for generations to come.  Conservation and preservation are two key components in ensuring that generations after the current one will be around to see resources, but how can the planet assist in these efforts if everyone is too sick from chemical exposure?    

Unknown Author, "De-inking Process", Paper Online

J.T. Baker, "Sodium Sulfide", Material Safety Data Sheet

Lenntech Water Treatment & Purification Holding B.V., "Pulp and paper industry water treatment", Lenntech

More about this author: Le Voir Lewis

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