Grad Student Develops Process to Recycle Paper Mill Waste

Shaul Lapidot (Hebrew University)

A graduate student at Hebrew University in Israel has developed a method for converting paper mill sludge into eco-friendly industrial foams. Shaul Lapidot (pictured right), a Ph.D. candidate in agriculture, also started a company that licensed the technology and plans to take the process to market.

A paper mill uses wood fibers long enough to form a fabric mesh from which paper is made, but those fibers account for only about half of the total fiber content in the pulp. The shorter fibers are normally washed away as sludge. Europe’s paper industry alone produces 11 million tons of sludge each year.

Lapidot has devised a process for making nano-crystalline cellulose (NCC) from paper mill waste. NCC is a raw material that can be further processed into a bio-based replacement for many synthetic foams now used in industry, such as for furniture and car interiors.

Conventional industrial foams are produced from polymers such as polyurethane, polystyrene, polyvinyl chloride (PVC), and polyethylene terephthalate (PET). Since all of these current foams rely on oil from fossil fuels, they present environmental challenges, and have environmental costs, such as regulatory or disposal restrictions.

Lapidot has found that fibers from paper mill sludge can be used to produce NCC because of their small dimensions which require relatively low energy and chemical input in order to process them into NCC. He also developed methods for processing NCC into nano-structured foams that can be used in the composite materials industry as bio-based replacements for conventional synthetic foams.

The NCC-based foams produced by Lapidot and his colleagues are porous and lightweight. They strengthened the basic foam material with furan resin, a cellulose-based resin produced from raw crop waste, such as found in sugar cane fields after harvest, oat hulls, corn cobs, and rice hulls. Lapidot says the reinforced NCC foams match the technical performance of current high-end synthetic foams.

Lapidot, with associates in Israel and Europe, started Melodea, a company to commercialize the process. Melodea has licensed the technology developed by Lapidot from Hebrew University’s technology transfer office.

Read more: Student Creates Self-Strengthening Nanocomposite Material

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