ABSTRACT
[Display omitted] • P(DAC-NIPAM) significantly improved the removal of levofloxacin and tetracycline. • P(DAC-NIPAM) had strong interaction with antibiotics for its multiple functional groups. • The hydrophobic groups on P(DAC-NIPAM) tightly bridged micelles of antibiotics and SDS. • Compact flocs were formed for shrinkage of P(DAC-NIPAM) molecule at the LCST. • Flocculation simulation further confirmed application feasibility of thermosensitive flocculants. Antibiotics were detected in worldwide natural water especially in COVID-19 period. The common flocculants rarely removed the dissolved antibiotics from natural water and wastewater. The flocculation improvement of organic polymer flocculants might solve the issue of antibiotic pollution or promote the removal efficiencies of antibiotics in water/wastewater treatment plants. Herein, a thermosensitive flocculant, P(DAC-NIPAM), was prepared via one-step method. It was investigated that the relationship between the various functional groups of P(DAC-NIPAM) and its flocculation performances in the treatment of simulated water containing levofloxacin, tetracycline, colloidal particles and natural organic matters. The removal mechanisms were discussed. The results indicated that the rich cationic, hydrophilic and hydrophobic groups of P(DAC-NIPAM) enhanced the interaction between flocculants and pollutants. The bridging of P(DAC-NIPAM) among micelles, charge neutralization, hydrogen bond between P(DAC-NIPAM) and two antibiotics, the shrinkage of P(DAC-NIPAM) molecule and enhancement of hydrophobicity when water temperature was above low critical solution temperature (LCST), co-flocculation and co-settlement of multiple pollutants all contributed to the efficient removal of levofloxacin and tetracycline from water. Flocculation simulation further confirmed that thermosensitive flocculant combined with heating plates was a potential candidate for antibiotic treatment in actual water treatment plants. [ FROM AUTHOR]
ABSTRACT
Antibiotics were detected in worldwide natural water especially in COVID-19 period. The common flocculants rarely removed the dissolved antibiotics from natural water and wastewater. The flocculation improvement of organic polymer flocculants might solve the issue of antibiotic pollution or promote the removal efficiencies of antibiotics in water/wastewater treatment plants. Herein, a thermosensitive flocculant, P(DAC-NIPAM), was prepared via one-step method. It was investigated that the relationship between the various functional groups of P(DAC-NIPAM) and its flocculation performances in the treatment of simulated water containing levofloxacin, tetracycline, colloidal particles and natural organic matters. The removal mechanisms were discussed. The results indicated that the rich cationic, hydrophilic and hydrophobic groups of P(DAC-NIPAM) enhanced the interaction between flocculants and pollutants. The bridging of P(DAC-NIPAM) among micelles, charge neutralization, hydrogen bond between P(DAC-NIPAM) and two antibiotics, the shrinkage of P(DAC-NIPAM) molecule and enhancement of hydrophobicity when water temperature was above low critical solution temperature (LCST), co-flocculation and co-settlement of multiple pollutants all contributed to the efficient removal of levofloxacin and tetracycline from water. Flocculation simulation further confirmed that thermosensitive flocculant combined with heating plates was a potential candidate for antibiotic treatment in actual water treatment plants.
ABSTRACT
As a vital component of public space, public open space (POS) is considered crucial for community regeneration. However, most evaluation studies have focused on the geographical attributes of POS, and those assessing renewal holistically in terms of residents’ everyday lives are limited. Drawing on the Ruijin community in Shanghai, this study compared networks of public space layout and residents’ daily behaviours as a function of their structure and individual nodes using the Social Network Analysis method to explore the characteristics and evaluate the effectiveness of renewal. The results showed: (1) the current renewal while increasing recreational opportunities and improving spatial appearance has had a limited effect at the social level. (2) There are differentiations between the two networks. POS plays different roles in the behavioural network, including comprehensive, intermediary, and directional nodes. (3) The core POSs have frequent interactions and strong links with specific types of public facilities than the periphery. Therefore, we suggested that POS renewal should be conducted according to the rule of “core preceding periphery, comprehensive high-efficiency preceding single low-efficiency” and explain the necessity of public participation in the process. These findings shed light on the potential mechanism of the impact of POS on everyday life and rethink the construction management and governance of urban community regeneration in the era of sustainability.
ABSTRACT
With the continuous expansion of urban construction land, the green belts aiming for ecological protection have ensured a sustainable and effective function of regional ecosystem services. At the same time, these ecological green belts are expected to develop their compound service potentials with the development of cities. In order to meet the increasing demand of urban residents for the recreational utilization of urban green space, the primary function of the ecological green belts has transformed from being purely ecological to a combination of being ecological and recreational. Based on social media data, which has the characteristics of a large amount of accessible geographic information, this study used multiple regression models to analyze the recreational utilization intensity of ecological protection green belts with a case study in the green belt of Shanghai, China. The research results showed that the internal elements (total external area, water area, etc.) of the Shanghai green belt have positive correlations with its recreational utilization. The impact of external factors was inconclusive on the recreational utilization of the outer forest belt (the number of subway stations in accessibility factors was negatively correlated; the number of cultural facilities and the number of restaurants in the surrounding service facilities were positively related). Combined with the "Shanghai City Master Plan (2017-2035)", this study suggests potential zones for the recreational transformation of the Shanghai green belt, provides a theoretical and practical basis for improving the recreational utilization of an urban ecological protection green belt and contributes to the sustainable development of ecological protection green belts in high-density cities.