TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Method: The method further comprises: desorbing the lignocellulosic material from the modified activated carbon after the step of separating the modified activated carbon from the solution; recovering the modified activated carbon after the step of desorbing the lignocellulosic material; burning the modified activated carbon having the lignocellulosic material adsorbed on it in a gasifier; extracting energy released from the step of burning the modified activated carbon having the lignocellulosic material adsorbed on it; recovering the modified activated carbon after the step of burning the modified activated carbon; and modifying a pH of the solution to a value of 5-10 prior to mixing the modified activated carbon with the solution. In the method, 1-100 g of modified activated carbon is provided per liter of the solution. In the method, prior to the step of mixing the modified activated carbon with the solution, comprises acidifying the solution and obtaining precipitated lignin, extracting the precipitated lignin, and neutralizing the solution. The method-I further comprises: desorbing the lignocellulosic organic material from the calcium carbonate or lime after the step of separating the calcium carbonate or lime from the mixture; adding lime mud to the mixture such that the lignocellulosic organic material is also adsorbed onto the lime mud, and subsequently separating the lime mud from the mixture; recovering the lime after the step of desorbing the lignocellulosic organic material; and burning separated lime for extraction of energy. In the method-I: the step of desorbing the lignocellulosic organic material is performed using a solvent extraction unit; and the step of burning separated lime includes recovering calcium oxide. The step of filtering the lignocellulosic solution with the filter is performed prior to the step of contacting the ion exchange resin with the lignocellulosic solution and extracting acetic acid onto the ion exchange resin. The adsorbent is activated carbon, which is modified prior to the step of mixing the adsorbent with the lignocellulosic solution by contacting the activated carbon with one of an oxidizing agent and a cationic polymer. The method-II further comprises: desorbing the lignin from the adsorbent after separating the adsorbent from the lignocellulosic solution; recovering the acetic acid from the ion exchange resin after separating the ion exchange resin from the lignocellulosic solution; and recovering the hemicellulose sugars from the filter after filtering the lignocellulosic solution. Preferred Components: The oxidizing agent comprises hydrogen peroxide, sulfuric acid, peroxy acid, or nitric acid. The oxidizing agent is hydrogen peroxide, and the step of contacting the activated carbon with the oxidizing agent includes mixing the activated carbon in a hydrogen peroxide solution having a concentration of 0.1-10 g/l, for 5-90 minutes, and at a temperature of 25-70 degrees C, where a weight percentage of activated carbon to hydrogen peroxide solution is 1-20%. The lignocellulosic solution is pulp production waste liquor, which is prehydrolysis liquor. The lime mud is present at 0-5 wt.%. The filter is a membrane filter. The filter comprises an ultrafiltration filter, a nanofiltration filter, or a reverse osmosis membrane filter. The lignocellulosic solution is pre-hydrolysis liquor from a Kraft-based dissolving pulp production process. In the method-II: a solids content of the pre-hydrolysis liquor is 4-12 wt.%; a pH of the pre-hydrolysis liquor is 3-5; an amount of the acetic acid relative to a total amount of dissolved organics within the pre-hydrolysis liquor is 15-25 wt.%; and an amount of the hemicellulose sugars relative to a total amount of dissolved organics within the pre-hydrolysis liquor is 25-45 wt.%. The activated carbon is contacted with 2-2.5 mg of cationic polymer per gram of activated carbon. The calcium carbonate or lime is present at 0.5-100 g of calcium carbonate or lime per liter of the lignocellulosic solution.    TECHNOLOGY FOCUS - POLYMERS - Preferred Components: The cationic polymer comprises: polydiallyldimethylammonium chloride or chitosan; and polyacrylamide, polyaluminum chloride, and/or amine-based cationic polymers. The cationic polymer is present at 0.1-10 mg of cationic polymer per liter of the lignocellulosic solution.