The development of cost-effective adsorbents with high sorption capacity and excellent renewability over a wide range of pH is essential for removal of toxic methylene blue (MB) from wastewater. The micro-mesoporous MCM-41 molecular sieve (M-MCM-41) was prepared by coal fly ash (CFA). The low temperature N 2 physical adsorption reveals that the prepared M-MCM-41 has hierarchically micro-mesoporous structure with high surface area (909.5 m 2 ⋅g À 1 ). As a result, M-MCM-41 possesses superior adsorption presentation towards MB with prominently high sorption capacity of 574.7 mg⋅g À 1 , and rapid sorption rate of 0.29 g⋅mg À 1 ⋅h À 1 (13 fold that of CFA). Surprisingly, 95 % of the incipient adsorption capacity remains well after five cycles. More importantly, the M-MCM-41 maintains almost the same maximum sorption capacity in the pH range of 5-9, which is close to the wastewater discharge standard (6 ∼ 9) without excessive pH adjustment. The adsorption kinetics and equilibrium data fit well with pseudo-secondorder model and the Langmuir isotherm model, respectively. And the thermodynamic investigations show that the adsorption behavior is spontaneous and exothermic. The M-MCM-41 has well-defined micro-mesoporous porosity and could be used as an effective adsorbent to remove MB from wastewater. This work provides a new sight for the solid waste resource utilization, which is beneficial to the development of recycling economy.

To investigate the genetic effects on the population of Coreius guichenoti of dam constructions in the upper reaches of the Yangtze River, we analyzed the genetic diversity and population structure of 12 populations collected in 2009 and 2019 using mitochondrial DNA (mtDNA) control regions. There was no significant difference in genetic diversity between 2009 and 2019 (P > 0.05), but the population structure tended to become stronger. Genetic differentiation (FST) among five populations (LX, BB, YB, SF and JA) collected in 2009 was not significant (P > 0.05). However, some populations collected in 2019 were significantly differentiated (P < 0.05), indicating that the population structure has undergone change. A correlation analysis showed that the genetic diversity of the seven populations collected in 2019 was significantly negatively correlated with geographical height (r = −0.808, P = 0.028), indicating that the populations at high elevations were more vulnerable than those at low elevations. In order to prevent the further decrease of genetic diversity and population resources, some conservation and restoration suggestions, such as fish passage and artificial breeding, are put forward.

In view of the merits of bioleaching and surfactant for sludge treatment, the possibility of surfactant with bioleaching pretreatment applied to improve sludge dewaterability was investigated in this work. The results showed that cetyl trimethyl ammonium chloride (CTAC) with bioleaching pretreatment was highly efficient in dewatering sludge. The optimal CTAC dosage and bioleaching pH for this combination were 120 mg/g (dry solids) and 3.55, respectively, under which the water content of filtrated cake was 68.94% and the specific resistance to filtration was 0.12 × 1013 m/kg with a reduction of 94.92%. Although CTAC and bioleaching both had positive effects on sludge dewatering, their combination was more efficient. The significant enhancement of sludge dewaterability was mainly contributed from the breakage and charge neutralization of sludge flocs, and the release of extracellular polymeric substances (EPS). In addition, the positive correlation between supernatant EPS concentration and sludge dewaterability was observed under experimental conditions.