Amine-functionalized cotton for the treatment of oily wastewater.

Common commercial demulsifiers are typically made from ethylene oxide and propylene oxide. The production process is dangerous and complex, with poor adaptability and high cost. In this work, cotton modified with polyethylene polyamine was utilized as a demulsifier for the treatment of oily wastewater. The chemical structure and morphology of the as-prepared sample (CPN) were characterized by IR spectrum and SEM. The effect of CPN dosage, pH value, and salinity on the demulsification performance of oily wastewater was explored through the bottle tests. The results showed that the light transmittance of separated water was 81.7% and the corresponding deoiling rate was 98.5% when a CPN dosage of 25 mg/L was used at room temperature for 30 min. The interfacial properties were also systematically investigated, and the results indicated that CPN had better interfacial activity and a stronger reduction capability of interfacial tension compared to asphaltenes. The finding initiated and accelerated the demulsification process of oily wastewater. Based on the outstanding performance of this biomass-derived demulsifier, it shows promising potential for application in the treatment of oily wastewater.

Depressive symptoms and physical activity among community-dwelling perimenopausal women: a prospective longitudinal study.

BACKGROUND: Women in perimenopause are vulnerable to depressive symptoms, and physical activity was reported to be a potential protective factor. The trajectories of physical activity and depressive symptoms over time and their longitudinal relationships in Chinese perimenopausal women have not been explored yet, leaving a research gap hindering us from better understanding and managing perimenopause depressive symptoms. METHODS: A multi-center prospective longitudinal study was conducted in four cities in Sichuan Province, China. Depressive symptoms and physical activity in perimenopausal women were collected in March 2019, June 2019, September 2019, and December 2019, respectively. Multivariable linear regression by generalized estimation equation was used to identify the relevant factors associated with depressive symptoms and physical activity. A four-wave autoregressive and cross-lagged panel model was performed to explore their longitudinal relationships. RESULTS: A total of 1875 women who completed the four-wave data collection were included in the data analysis. Depressive symptoms exacerbated over time and were associated with women's age, monthly income, marital status, chronic disease, and negative life events. Physical activity decreased over time and was associated with educational background and monthly income. According to the cross-lagged panel model, perimenopausal women with more severe depressive symptoms tended to be less physically active, and similarly, perimenopausal women with less physical activity were more prone to report more severe depressive symptoms. CONCLUSION: The cross-lagged panel model disclosed longitudinal bidirectional relationships between depressive symptoms and physical activity in perimenopausal women. Appropriate physical activity should be recommended for perimenopausal women to improve their mental well-being. Tailored physical activity duration and maintenance measures should be proposed based on different sociodemographic statuses.

Finger exercise alleviates mild cognitive impairment of older persons: A community-based randomized trial.

Mild cognitive impairment (MCI) is common in the older population, with a lifetime progression rate into dementia of 60% to 65%, which has highlighted the importance and realistic value of management of MCI in the context of global aging. We conducted a randomized controlled trial involving 232 participants (117 in the intervention group, 115 in the control group) to determine the effect of finger exercise on the cognitive function of community-dwelling older persons with MCI. The Mini-Mental State Exam (MMSE) was used to measure cognitive function at baseline and the end of the study. After controlling for sociodemographic variables, the effect of finger exercise on MCI was assured and with a large effect size [F(1,21) = 106.351, p < 0.001, ηp2 = 0.325]. Finger exercise could serve as an economic and convenient alternative to the early-stage management of MCI, while more research is in need to further support this finding.

Demulsification of water-in-crude oil emulsion driven by a carbonaceous demulsifier from natural rice husks.

Removing emulsified water from a water-in-crude oil (W/O) emulsion is critically required prior to downstream processing in the petroleum industry. In this work, environmentally friendly and amphipathic rice husk carbon (RHC) demulsifier was prepared by a simple carbonization process in a muffle furnace using rice husks as starting materials. RHC was characterized by field-emission scanning electron microscope, energy dispersive spectrometer, Fourier transform infrared spectrometer, ultraviolet-visible spectrometer, powder X-ray diffraction, zeta potential and synchronal thermal analyzer. The factors such as dosage, temperature, settling time, pH value and salinity were systematically investigated. The results indicated that the dehydration efficiency (DE) reached as high as 96.99% with 600 mg/L of RHC for 80 min at 70 °C. RHC exhibited an optimal DE under neutral condition, but it was also effective under acidic and alkaline conditions. Also, it had an excellent salt tolerance. The possible demulsification mechanism was explored by interfacial properties, different treatment methods for RHC and microexamination. The demulsification of RHC is attributed to its high interfacial activity, oxygen-containing groups and content of silica. It indicates that RHC is an effective demulsifier for the treatment of the W/O emulsion.

Recyclable amine-functionalized carbon nanotubes for the separation of oily wastewater.

In this work, a CNTs-NH2 demulsifier was prepared by grafting ethylenediamine on the surface of carbon nanotubes to break oily wastewater. The physicochemical and interfacial properties of CNTs-NH2 were characterized and analyzed. It showed that CNTs-NH2 had an eminent amphipathicity and high interfacial activity, which allows it to sharply migrates to the interface and effectively interacts with interfacial film by the combined action of π-π interaction and electrostatic attraction. The demulsification tests exhibited that CNTs-NH2 could effectively remove emulsified oil from the oily wastewater. It could be used at acidic and neutral conditions, and high salinity. Moreover, it could be recycled and still maintained its interfacial activity, thusly vastly enhancing the application scope. The light transmittance was up to 88.1% and the corresponding oil removal rate was 99.2% with 100 mg/L of CNTs-NH2 for 30 min. The oil removal rate of CNTs-NH2 remained above 97.8% after 6 cycles. This work provides a deep understanding on the design of demulsifier and its demulsification mechanism.