Superefficient removal of lignins from papermaking wastewater by polycationic adsorption and direct reuse of wastes: structure–activity relationships and interaction mechanisms

Abstract

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.

A super-efficient polyquaternium gel that can remove over-10-times masses of lignins from wastewater for resourcefulness

“…2b. According to the average values of the equilibrium adsorption capacities (q e ) at the saturated adsorption states (i.e., at the dosages being 0.001-0.009 g), the adsorption capacity of SGPQG skeleton components for lignin was 7507.66 mg•g -1 , which is 1.89 times higher than that of similar material model without the chain segmentation (i.e., the PPG material) obtained in the pre-work 26 (Supplementary Fig. 1), indicating that the chain segment modification of polyquaternium gel played an efficient role in improving the removal of lignin.…”

“…Compared to the existing inner skeleton-space effects discovered in our previous works 26,27 , the outer skeleton-space effects had been additionally expanded in this new integrated skeletonspace effect mechanism. The mechanism model could be intuitively drawn as shown in Fig.…”

“…In the preliminary work, we focused on the integration of interaction mechanism innovation and wastewater purification, to launch a series of researches for developing polyquaternium water-purification materials [26][27][28][29][30] . It was found that some of the polyquaternium gel adsorbent materials, when being used for purifying papermaking wastewater, could remove 3.89-8.28 times of their own mass of lignins per unit mass 26,27 . This desirable effect could be attributed to the adsorption of lignins by the skeletons of the gel materials and the self-condensation effect of lignins inside the skeleton spaces (Fig.…”

Time-Resolved Killing of Individual Bacterial Cells by a Polycationic Antimicrobial Polymer

“…Polycations are positively charged polymeric materials that often display antimicrobial properties − and are utilized in the food industry and water treatment and in the design of antimicrobial surfaces. , While research on polycations is widespread, the mechanisms of antimicrobial action are not fully understood, and an improved understanding could lead to improved performance. Various mechanisms have been proposed, which all begin with adsorption of polycation onto the cell surface, − followed by an increase in membrane permeability, which leads to death .…”

Eco‐environmental benefits analysis of EcoPartnerships program of production technology of calcium carbonate from lime mud produced by alkaline papermaking

“…4 Papermaking wastewater is recognized as the main environmental pollution source in the world. 5,6 At present, the treatment methods of papermaking wastewater at home and abroad have been relatively mature, such as alkali recovery, coal water slurry (composite) additives, acid leaching and biochemical method, and so on. 7,8 Among them, the most common and most applied technology is alkali recovery, and the treatment of papermaking wastewater has been basically realized through this technology.…”