PAPERmaking! FROM THE PUBLISHERS OF PAPER TECHNOLOGY Volume 6, Number 2, 2020
overcome the dynamic characteristic difficulties of process data in monitoring. Compared with DBN and back propagation neural network (BPNN), the GA-DBN effectively achieved a better predictive accuracy than other tests models in complex wastewater treatment processes. The value of the coefficient of determination of GA-DBN model is increased by 1.71 – 1.86% and 5.21 – 9.32%, respectively. The GA-DBN model can be structured with fewer variables or samples to describe the complex paper-making wastewater treatment process, obtaining the better model performance and predictive accuracy. Superefficient removal of lignins from papermaking wastewater by polycationic adsorption and direct reuse of wastes: structure – activity relationships and interaction mechanisms, Yu Bai, Hongyan Li, Qiwen Yang, Yikai Yu & Bingxian Peng, Journal of Cleaner Technology and Biotechnology , 95(11), Nov. 2020, https://doi.org/10.1002/jctb.6460. 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 lignin s 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 Ǧ 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 Ǧ 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. Demonstration on the treatment of paper Ǧ making wastewater by a full Ǧ scale IC Ǧ A/O Ǧ membrane reactor system for reclamation, Haifeng Zhuang, Zhong Cheng, Shengdao Shan, Haitao Shen & Bingjun Zhao, Journal of Chemical Technology and Biotechnology , 95(12), Dec. 2020, https://doi.org/10.1002/jctb.6494. In this study, the performance of a full Ǧ scale internal circulation – anoxic/oxic (IC Ǧ A/O) – ultrafiltration (UF) – reverse osmosis (RO) membrane system for reclamation and reuse of paper Ǧ making wastewater was investigated. Results showed that the integrated system presented a stable and highly efficient performance. The effluent concentrations of chemical oxygen demand, total organic carbon, biochemical oxygen demand, NH4+ nitrogen and total nitrogen were 12, 4, 0.3, 0.5 and 2.9 mg L−1. gas chromatographic– mass spectrometric results showed that the organic composition in each process of the IC Ǧ AO Ǧ UF Ǧ RO system varied significantly. Acute biological toxicity was obviously reduced, with an effluent toxic unit value of 3.11. The results of particle size distribution indicated that anaerobic granular sludge (around 3 mm) was formed in an IC reactor. Anaerolinea, Propioni ciclava and Thauera were the main contributors to pollutant removal. Advanced treatment by the UF Ǧ RO system achieved complete removal of suspended solids, silt density index and turbidity with little hardness and conductivity in the final effluent, which allowed for reclamation of paper Ǧ making wastewater. Conclusion: Water reuse and energy recycling were successfully realized in the built Ǧ up IC Ǧ AO – membrane reactor system.
Technical Abstracts
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