BACKGROUND As a complex phenol polymer pollutant, lignin is the most difficult to remove in papermaking wastewater. RESULTS This work first found a strong adsorbent for highly efficient removal of lignins and realized the direct reuse of its wastes. Through systemically screening the serial molecular structures of polycationic adsorbents previously developed, a highly permeable polycationic gel (PPG) adsorbent was discovered to be the most suitable for lignin removal. The maximum adsorption capacity of PPG for the lignins was 3891.65 mg/g, that is, the masses of adsorbed lignins were 3.89 times higher than that of PPG. Interestingly, after adsorbing the lignins, PPG wastes could be directly reused, without any treatment, for purifying dyeing wastewater. The adsorption capacity of PPG wastes reused for adsorbing the anionic dyes was 245.05 times higher than that of the existing activated carbon, indicating that PPG wastes maintained excellent adsorption ability for purifying the dyeing wastewater. A series of simulation experiments and instrument analyses were carried out to detect the new adsorption effect of PPG. The high water-permeability of PPG allows for complete permeability of the lignins and easy adsorption inside PPG. After adsorption, shrinkage of the internal structure of PPG and aggregation of the adsorbed lignins on the surface of PPG enhanced the adsorption intensity of PPG toward the lignins. CONCLUSION This indicated that PPG had a super-high adsorption ability for direct removal of lignins from water by adsorption, which marked the first successful report of reused wastes utilized for treating other waste pollutants. (c) 2020 Society of Chemical Industry