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Shanghai is one of the world-leading megapolises facing the challenge of ecological sustainable development. The recyclable waste from households (RWH) generated in Shanghai has increased rapidly since the implementation of garbage classification in 2019. However, there are no rigorous data on the generation and collection of RWH, and the corresponding countermeasures are required to be studied. This paper attempted to investigate RWH generation and identify the effects of RWH recycling in Shanghai. We used questionnaires combined with a field survey to investigate the competent authorities and leading recycling enterprises to analyze the characteristics of RWH generation. We conducted a monthly survey of 52 leading recycling enterprises in 11 typical districts for 2020. We also identified the main influencing factors of RWH generation using a multiple linear regression model. In addition, we popularized the model to estimate Shanghai’s RWH generation rate. Results show that data from leading recycling enterprises surveys were more accurate and reached a maximum of 82,104.77 kg/cap/month in November 2020. Higher RWH generation was found in suburban districts at 36,396.20 kg/cap/month. Shanghai’s RWH generation rate was 6253.60 t/d through model calculation. The educational level of household managers, regional economic condition, resident population, and disposable income impact RWH generation. Based on the abovementioned results, the implications for RWH management were discussed. We propose to promote the combination of theoretical simulation and information data platform construction. Meanwhile, it is also necessary to improve the capacity of the collection and transport system and accelerate the construction of pre-treatment bases in Shanghai.

Heterogeneous activation of peroxymonosulfate (PMS) is one of the most promising techniques for wastewater treatment. Herein, an ingenious system by coupling of photocatalysis and PMS activation was developed, using hollow-structured amorphous prussian blue (A-PB) decorated on graphitic carbon nitride (g-C3N4) as the catalyst. Degradation of bisphenol A (BPA) via the A-PB-g-C3N4 mediated PMS activation under visible light (Vis) was systematically investigated. Astonishingly, it was found that ~ 82.0%, 92.6%, 98.2% and 99.3% of BPA (40 mg/L) were removed within 2, 4, 6 and 7 min, respectively, suggesting the extremely strong oxidizing capacity of the A-PB-g-C3N4/PMS/Vis system. Synergistic effect between the decorated A-PB and the g-C3N4 substrate promoted the Fe(III)/Fe(II) redox cycling and facilitated the charge transfer at the A-PB/g-C3N4 heterojunction interface. As a result, both photocatalysis and heterogeneous activation of PMS were boosted in the A-PB-g-C3N4/PMS/Vis system, leading to the production of large amount of reactive oxygen species (ROS). The various ROS (SO4•–, HO•, •O2– and 1O2) was responsible for the ultrafast degradation of BPA. Moreover, the A-PB-g-C3N4 catalyst also exhibited outstanding reusability and stability, retaining 98.9% of the removal percentage for BPA after five consecutive reaction cycles. This study suggests that the A-PB-g-C3N4 can be an all-rounder to bridge photocatalysis and PMS activation, and shed a new light on the application of multiple ROS for the ultrafast elimination of micropollutants from wastewater.

With the improvement of people's living standard in China, the amount of municipal solid wastes (MSW) has been increasing year by year, and resulted in serious environmental issues. Developing diverse classification and recycling technologies for treating municipal solid wastes is an effective solution to such problem, which can maximizes the utilization of wastes, reduces the amount of waste disposal and improves the living environment. This paper analyzes the Shanghai municipal wastes sorting programmed and concludes the following reasons for its first-stage success, including a well-designed recycling structure, a high-value food wastes reduction and recycling system, a low value-added wastes re-utilization system, various treatment technologies and the corresponding policy supports.

Quantum dots (QDs) derived from two-dimensional (2D) nanosheets (NSs), especially ultrathin transition metal dichalcogenide (TMD, e.g. WS2, WSe2, MoS2, MoSe2) NSs, have attracted great attention due to their broad band absorption and high charge mobility. Herein, WS2 QDs, one of the emerging extraordinary zero-dimensional (0D) TMD materials, were applied to the preparation of novel 0D/2D heterojunctions of WS2 QDs/BiOCl nanosheets. The obtained WS2/BiOCl composites exhibited significantly enhanced visible-light-driven photocatalytic activity as compared with pure BiOCl. The results indicated that the holes (h+) and O2˙− are the main active species generated by the catalysts under visible light irradiation. The enhanced photocatalytic performance could be due to the broad band absorption and up-conversion properties of the WS2 QDs as well as the band alignment and the strong coupling between the WS2 QDs and BiOCl NSs, leading to a broadened light absorption range and enhanced efficiency for electron–hole pair production and separation. These findings offer exciting opportunities using the extraordinary 2D TMD material-derived quantum dots for the fabrication of novel 0D/2D composites and may provide new insights into the application of the novel 0D/2D composites in catalysis.

Graphene-based multifunctional composites were prepared by encapsulating of magnetic ZnFe2O4@chitosan (ZnFe2O4@CS) particles into graphene oxide (GO) layers. The obtained ZnFe2O4@CS/GO were characterized using scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. Adsorption of basic fuchsin (BF) onto the ZnFe2O4@CS/GO was investigated using pH, adsorption time, initial BF concentration and temperature. Kinetic data and adsorption isotherms were better fitted by a pseudo-second-order kinetic model and Langmuir isotherm model, respectively. The values of activation parameters such as free energy (ΔG, −14.02 to −16.56 kJ mol−1), enthalpy (ΔH, 23.27 kJ mol−1) and entropy (ΔS, 127.75 J mol−1 K−1) were calculated, suggesting that the adsorption was a spontaneous, favorable and endothermic process in nature. The results demonstrated that the ZnFe2O4@CS/GO composites are potentially suitable materials for the removal of organic dyes from large volumes of wastewater.

Bamboo-like carbon nanotubes (b-CNTs) were synthesized via a low-cost one-pot approach by using FeCl3 and self-assembled colloidal polymer nanoplates as precursors. The resulting b-CNTs were applied as both the adsorbent and the catalyst for the removal of bisphenol A (BPA) from aqueous solutions. The maximum adsorption capacity of BPA on the b-CNTs calculated by using the Langmuir model is 328.6 mg g−1 at 303 K. Thermodynamics studies revealed that the adsorption was spontaneous and exothermic. With the synergistic effect of adsorption and catalysis by the b-CNTs, BPA (70 mg L−1) was almost completely removed (over 97%) at pH 7.0 within 80 min after the adsorption–oxidative degradation process. The b-CNTs also displayed an excellent reusability for the catalytic oxidation of BPA (initial concentration of 70 mg L−1) with the degradation ratio remaining at 84% after 5 cycles. Moreover, the b-CNT catalysts can be easily recycled by using an external magnet and regenerated by simply washing. This study not only presents a cost-effective method of using magnetic nanocarbons for the cleanup of pollutants, but also demonstrates the potential application of the b-CNTs as both an adsorbent and a catalyst.

In this work, nitrogen-rich graphene-like carbon sheets (N-GLCS) with high specific surface area (488.4m2/g), narrow pore distribution and high N-doping (18.4 at%) were prepared and applied as both adsorbent and catalyst for the removal of bisphenols. Adsorption experiments demonstrated the high adsorption capacities of the N-GLCS toward bisphenol F (BPF) (222.9mg/g), bisphenol A (BPA) (317.8mg/g), and bisphenol C (BPC) (540.4mg/g). Results showed that about 98.6% of BPA (70mg/L) was removed at pH 7.0 within 80min after the adsorption-catalytic degradation process. The N-GLCS also showed a superb reusability for the catalytic oxidative degradation of BPA (70mg/L) with the removal percentage maintains over 83% after 5 cycles. With the synergistic combination of the excellent adsorption and catalytic properties of the N-GLCS, trace amount of pollutants can be preconcentrated and immobilized at the surface of N-GLCs, at the same time, active radicals were also produced at the surface of the N-GLCS by the activation of peroxydisulfate (PS), and finally the pollutants can be degraded in-situ by the active radicals. These findings provide a new avenue towards the efficient removal of trace-level EDCs from water solution by using the coupled adsorption-advanced oxidation processes.