Method for separating and recovering lignin derivatives

The method as in claim 1, wherein the metal oxide is an oxide of one or more metals selected from the group consisting of titanium, zinc, iron, cobalt, nickel, copper, tin, indium, lead, and niobium.

The method as in claim 1, wherein the metal oxide comprises a semiconductor material.

The method as in claim 1, wherein the metal oxide comprises the metal oxide particle of average particle size less than or equal to 300 nm.

The method as in claim 1, wherein the liquid medium is selected from the group consisting of an aqueous medium, a non-aqueous medium and mixture thereof.

The method as in claim 1, wherein the lignin derivative is dissolved or dispersed in the liquid medium.

The method as in claim 1, wherein the lignin derivative is one or more lignin derivatives selected from the group consisting of following (a) to (d):n(a) a ligno-phenol derivative which is a phenol-derivative of lignin, the ligno-phenol derivative obtainable by solvating a lignin containing material with a phenol compound and then mixing the solvated lignin containing material with an acid;(b) a secondary derivative obtainable by modifying the ligno-phenol derivative with a functional group selected from the group consisting of an acyl group, a carboxy group, an amido group, and a cross-linking group;(c) a secondary derivative obtainable by treating the ligno-phenol derivative with an alkali; and(d) a higher order derivative obtainable by modifying the ligno-phenol derivative with at least two modifications selected from the following modifications:nintroduction of an acyl group, introduction of a carboxy group, introduction of an amido group, introduction of a cross-linking group and an alkali-treatment.

The method as in claim 1, wherein the recovering is performed at a temperature of less than or equal to 60° C.

The method as in claim 13, wherein the lignin derivative is a ligno-phenol derivative of a lignin obtainable by solvating a lignin containing material with a phenol compound and then mixing the solvated lignin containing material with an acid; and during the separation step the ligno-phenol derivative is contacted with the metal oxide added to the liquid medium prior to the formation of the ligno-phenol derivative.

The method as in claim 13, wherein the lignin derivative is a ligno-phenol derivative of a lignin obtainable by solvating a lignin containing material with a phenol compound and then mixing the solvated lignin containing material with an acid; and during the separation step the ligno-phenol derivative is contacted with the metal oxide added to the liquid medium after the formation of the ligno-phenol derivative.

The method as in claim 17, wherein the composite material comprises a used product.