The present invention involves an environmentally friendly process and apparatus for the delignification of lignin-containing materials, such as cardboard newspaper or agricultural or tree pruning wastes. This process produces cellulose using low temperatures and low concentrations of hydrogen peroxide. It can be performed using a column fitted with a semipermeable gasket that pressurizes the column by retaining oxygen released by action of the hydrogen peroxide on a lignin-containing material.

Processes for converting lignocellulose to feedstock and downstream products are disclosed. The processes may include acid treatment of lignocellulose to produce a fermentation feedstock. In various instances, the processes include recovery or recycling of acid, such as recovery of hydrochloric acid from concentrated and/or dilute streams. Downstream products may include acrylic acid-based products such as diapers, paper and paper-based products, ethanol, biofuels such as biodiesel and fuel additives, and detergents.

The purpose of the present disclosure is to provide a recovery method for an organic acid. The recovery method makes it possible to efficiently recover an organic acid that is included in a deactivating aqueous solution that includes excrement. This recovery method has the following features. A method for recovering an organic acid that deactivates a highly water-absorbent polymer that is included in used absorbent articles, the method being characterized by including: a deactivation step (S1) in which the highly water-absorbent polymer is immersed in a deactivating aqueous solution that includes an organic acid and has a prescribed pH and the highly water-absorbent polymer is deactivated; a highly water-absorbent polymer removal step (S2) in which the deactivated highly water-absorbent polymer is removed from the deactivating aqueous solution; a pH adjustment step (S3) in which the deactivating aqueous solution is adjusted to a prescribed pH; a concentration step (S4) in which the deactivation step (S1), the highly water-absorbent polymer removal step (S2), and the pH adjustment step (S3) are repeated using deactivating aqueous solution that has gone through the pH adjustment step (S3) and the organic acid in the deactivating aqueous solution is concentrated; and an organic acid recovery step (S6) in which the organic acid is recovered from the deactivating aqueous solution.

Pulp fiber containing little ash is effectively recovered from a used sanitary product containing the pulp fiber and a polymer absorbent. The method according to the present invention comprises: a step for treating the used sanitary product with an ozone-containing gas and thus decomposing and removing at least a portion of the polymer absorbent in the used sanitary product; and a step for stirring the used sanitary product, that has been treated with the ozone-containing gas, in water or an aqueous solution containing an antiseptic and thus decomposing the used sanitary product into constituents. If required, the method may further comprise a step for separating the pulp fiber from the decomposition product obtained by the decomposition step.

A method is provided for recovering pulp fibers having little damage from a used absorbent article that contains pulp fibers and a superabsorbent polymer. The used absorbent article is treated at a temperature of greater than or equal to 80 C. with an organic acid aqueous solution having a pH no greater than 2.5, and the superabsorbent polymer is deactivated. Preferably, the pulp fibers and the deactivated superabsorbent polymer are separated from the used absorbent article after treatment with the organic acid aqueous solution, and further, a mixture including the separated pulp fibers and deactivated superabsorbent polymer is treated with an oxidizing agent, the deactivated superabsorbent polymer is decomposed, reduced in molecular weight and solubilized.

A high efficiency bleaching method for cellulosic pulp includes: (a) providing a charge of aqueous cellulosic pulp to a bleaching vessel at a consistency of from 10% to 30% along with a peroxy bleaching agent and an alkaline agent effective to adjust pH of the charge to 9.5 to 12.5; and (b) bleaching the aqueous cellulosic pulp in the bleaching vessel while maintaining a bleaching temperature of from 110 F. (43 C.) to 135 F. (57 C.) and a pH of the charge from 9.5 to 12.5 for an extended bleaching retention time. The bleaching method is advantageously used to bleach low brightness recycle pulp, and/or as part of a multistage process with bleaching stages of lesser duration, and/or as a high peroxy efficiency, low dose bleaching process or in connection with concurrently storing and bleaching pulp.

Unique, inexpensive, and strong biocomposites are obtained from blending cellulose matrix materials pith lignocellulosic reinforcement materials with the aid of alkaline aqueous solvent and cold temperatures. These lignocellulosic composites (LCs) are produced without use of any thermoplastic resins, adhesives, catalysts, plasticizers or d chemical or physical procedures. The LCs include a matrix and a reinforcement material. The matrix is a cellulose material (e.g., cotton, hemp, flax, or wood) that is liquefied using an aqueous alkaline solvent solution under cold temperatures to more readily adhere and or incorporate/encapsulate the lignocellulosic reinforcements (wood chips, fibers, and other lignocellulosic sources).

The purpose of the present invention is to provide a recycled pulp fiber manufacturing method with which it is possible to easily obtain recycled pulp fibers containing less of a high water-absorption polymer without requiring any mechanical equipment such as an ozone generation apparatus. This method is for manufacturing recycled pulp fibers from used sanitary goods including pulp fibers and a high water-absorption polymer, and is characterized by comprising: an inactivation step (S1) for immersing a sanitary goods constituent material in an acid-containing aqueous solution so as to inactivate the high water-absorption polymer; a high water-absorption polymer degradation step (S3) for generating chlorine dioxide by adding a chlorine dioxide generating material, which is capable of generating chlorine dioxide through reaction with an acid, to the acid-containing aqueous solution that has undergone the inactivation step (S1), and then degrading the inactivated high water-absorption polymer using said chlorine dioxide; and a recycled pulp fiber recovery step (S4) for recovering the recycled pulp fibers from the acid-containing aqueous solution that has undergone the high water-absorption polymer degradation step (S3).

Provided is a method for producing pulp fibers to be saccharified, whereby it becomes possible to reduce the amount of a highly water-absorbable polymer and therefore increase the collection efficiency in the production of a saccharified solution when pulp fibers for a saccharified liquid is produced from a dirty absorbent article. The method is a method for producing pulp fibers to be saccharified, from pulp fibers in a dirty absorbent article. The method includes: a solid-liquid separation step (S18) of crushing up a highly water-absorbable polymer while separating an inactivated aqueous solution containing pulp fibers and the highly water-absorbable polymer both separated from a dirty absorbent article into a solid material (98) containing the pulp fibers and the highly water-absorbable polymer and a liquid material (E) containing the highly water-absorbable polymer and the inactivated aqueous solution; and a removal step (S21) of washing away the remaining highly water-absorbable polymer by washing the separated solid pulp fibers in a solution or another means to produce pulp fibers to be saccharified.

The objective of the present disclosure is to provide a method for easily evaluating the degree of cleanliness of recycled material derived from used sanitary products. The evaluation method according to the present disclosure has the following configuration. This method for evaluating a degree of cleanliness of recycled material derived from used sanitary products includes: a preparation step of preparing a dispersed aqueous solution in which the recycled material is dispersed in water a separation step of subjecting the dispersed aqueous solution to centrifugal separation to separate the dispersed aqueous solution into a liquid component and a solid component; and a measuring step of measuring the concentration of protein in the liquid component using a protein measuring means.