Abstract: Disclosed is a process for the extraction of silica from lignocellulosic plant matter, including the steps of: a) fractionating the lignocellulosic plant matter in the presence of an acid solution, so as to obtain a solid fraction including cellulose; b) extracting the silica from the solid fraction obtained in step a) with a basic solution, at a pH between 10 and 13 and at a temperature between 70° C. and 90° C., so as to obtain a liquid phase including silica and a solid phase; c) separating the liquid phase and of the solid phase which are obtained in step b); and d) precipitating the silica which is included in the liquid phase, at a pH between 5 and 6.

Abstract: A process for preparing a cellulosic sponge includes the steps of treating an aqueous suspension of cellulose fibers with periodate; adjusting the pH of the resulting dialdehyde cellulose fibers suspension to a value between 2.5 to 5.5; freezing the suspension obtained and thawing the three dimensional structure to render the cellulosic sponge. The process may further include a step of drying to render a cellulosic foam. Both the new sponge and the new foam may also be further chemically modified obtaining a broad variety of derivatives with tailored properties which are useful in many different applications.

Abstract: Disclosed is a process for the extraction of silica from lignocellulosic plant matter, including the steps of: a) fractionating the lignocellulosic plant matter in the presence of an acid solution, so as to obtain a solid fraction including cellulose; b) extracting the silica from the solid fraction obtained in step a) with a basic solution, at a pH between 10 and 13 and at a temperature between 70° C. and 90° C., so as to obtain a liquid phase including silica and a solid phase; c) separating the liquid phase and of the solid phase which are obtained in step b); and d) precipitating the silica which is included in the liquid phase, at a pH between 5 and 6.

Abstract: A process for preparing a cellulosic sponge includes the steps of treating an aqueous suspension of cellulose fibers with periodate; adjusting the pH of the resulting dialdehyde cellulose fibers suspension to a value between 2.5 to 5.5; freezing the suspension obtained and thawing the three dimensional structure to render the cellulosic sponge. The process may further include a step of drying to render a cellulosic foam. Both the new sponge and the new foam may also be further chemically modified obtaining a broad variety of derivatives with tailored properties which are useful in many different applications.