Destruction of PFOA on Ion-exchange Resin with Advanced Reduction Processes to Regenerate Resins for Addressing PFOA Pollution in Drinking Water

Per- and polyfluoroalkyl substances (PFAS) have been globally incorporated into various industrial and consumer products since the 1940s. However, concerns about PFAS have gradually grown because of their prevalence, mobility, persistence, bioaccumulation, and adverse impacts on human and environmental health. Unfortunately, traditional water treatment processes inefficiently remove PFAS. Therefore, there is an urgent research need to develop innovative, technically viable, and low cost-treatment processes for the removal of PFAS in water. Among the established PFAS treatment technologies, ion-exchange (IX) has been extensively applied to drinking water treatment practices due to its adsorption capability and technology maturity. However, IX is highly cost-inefficient and environmentally unfriendly because of the expenses associated with off-site regeneration, no PFAS detoxification, and the production of harmful PFAS-containing regenerant waste required for careful disposal. In contrast, advanced reduction processes (ARPs) have demonstrated technical viability for PFAS degradation due to the powerful reducing potential of hydrated electron (eaq -) generated. Nevertheless, ARPs are restricted in realistic water treatment, particularly drinking water treatment, due to increased total dissolved solids in effluent, operational requirements in pH adjustment, and depletion of dissolved oxygen. The primary objective of this dissertation is to advance the fundamental understanding of the interactions of eaq - and PFAS-laden IX resins, thereby providing a scientific basis for the development of an innovative on-site ARP-based IX resin regeneration method capable of recovering spent resins and degrading PFAS in drinking water treatment. Specifically, the design comprises repeated IX adsorption – ARP regeneration phases. In the first adsorption phase, trace PFAS in water is captured by IX resins until saturation. Subsequently, ARPs are launched to decompose PFAS laden on the resins for adsorption recovery before reuse. In the dissertation research, perfluorooctanoic acid (PFOA) was chosen as a model PFAS species owing to its prevalence in the aquatic environment, while ultraviolet (UV)/sulfite was selected as the representative ARP to generate eaq -. Five tasks were sequentially completed in this dissertation to achieve the primary objective. In Task 1, a critical review of the destruction of aqueous PFAS with ARPs was conducted to retrospect the state-of-the-art knowledge on the emerging PFAS treatment technology and identify the critical knowledge gaps toward applications to drinking water treatment. In Task 2, bench-scale tests were performed to screen for a potentially durable resin to demonstrate the technical feasibility of eaq --driven ARPs for mitigation and degradation of PFAS laden on resins. Specifically, IRA67 resins were selected among eight commercially available resins for the subsequent dissertation studies because of their excellent PFOA adsorption capability and durable physical/chemical properties for consistently high PFOA. In Task 3, bench-scale tests were carried out to elucidate the interactions of eaq - and PFOA sorbed on the PFOA/NOM-laden IRA67 resins and assess the role of NOM co-sorbed on the IX resins in the proposed PFAS treatment approach. Results showed that PFOA, regardless of sorbed or aqueous states, could be effectively degraded by eaq -. However, UV/SO3 2- ARP treatment could not effectively decompose co-sorbed NOM to substantially recover the resin adsorption effectively. The buildup of NOM on the resins finally led to the loss of the resin capacity for capturing PFOA in water with the increasing cycle number. Therefore, two pretreatment strategies (i.e., coagulation and UV/hydrogen peroxide (H2O2)-based advanced oxidation process (AOP)) were assessed in Task 4 to alleviate NOM loading on PFOA/NOM-laden IRA67 and to evaluate the effect of pH on desorption of co-sorbed NOM during the IRA67 regeneration processes, respectively. Moreover, the optimized cyclic adsorption-regeneration tests combined with the NOM mitigation strategies were evaluated for the repeated removal of PFOA in water. Results showed that alum coagulation at the optimized operational conditions (i.e., alum 60.0 mg/L; pH 6.0) significantly alleviated the NOM loading on IRA67, but the UV/H2O2-based AOP could not further reduce the PFOA loading on IRA67. The continuous adsorption of PFOA by IRA67 in the cyclic adsorption-regeneration process was ascribed to NOM desorption at pH 10.0 during the ARP regeneration process to release more occupied sites on IRA67. Therefore, the UV/SO3 2- process operated at an alkaline condition, if jointly used with alum coagulation as a pretreatment step, can enable a promising on-site regeneration process for the PFOA/NOM-laden IRA67 in drinking water. The information will be input to Task 5 in which the implications of the proposed ARP-based resin regeneration technologies were discussed in terms of economic, environmental, and social aspects, major conclusions were summarized, and future research directions were identified. The dissertation builds a basis for an innovative ARP-enabled on-site IX regeneration approach to PFAS pollution in drinking water treatment. The resin adsorption capacity can be substantially recovered, accompanied by the PFAS degradation and the production of a small volume of easily managed regenerant waste

Emergency Water Treatment with Ferrate(VI) in Response to Natural Disasters

The frequency and magnitude of natural disasters (e.g. hurricanes) have increased globally over the past century. Clean water is a top priority for disaster-affected populations. However, existing emergency water treatment (EWT) methods are not all feasible or technically effective in many emergency situations. The recent Puerto Rican water crisis after Hurricane Maria highlights the research needs and new challenges for new EWT technologies. In this study, bench scale experiments were carried out to evaluate ferrate(vi) for the treatment of simulated disaster-polluted water. Results show that ferrate(vi) treatment could simultaneously and effectively inactivate bacterial indicators, remove metal and metalloid contaminants, degrade dissolved organic matter, and reduce turbidity, while insignificantly increasing total dissolved solids (TDS) to ensure an acceptable TDS ≤ 1000 mg L-1 (the recommended minimum TDS standard for an emergency water supply). The ferrate(vi) dose played a key role, because it directly influenced the removal efficiencies and also affected the size distributions of iron and metal/metalloid contaminants after treatment. As the ferrate(vi) dose increased, the fractions of soluble and colloidal iron and metal/metalloid contaminants decreased, while their particulate portions increased, implying that the contaminants were associated with ferrate(vi) resultant iron particles. Therefore, an increased ferrate(vi) dose could accelerate the aggregation of fine iron particles, thereby facilitating the removal of associated toxic metals and metalloids in ensuing solid-liquid separation. Ferrate(vi) opens a new opportunity for EWT to provide safe and sufficient water for disaster-affected populations and rapid disaster relief. The knowledge can also be applied to ferrate(vi) treatment design for municipal water treatment and reuse, supporting urban water sustainability

Prospect of concentrating solar power in China--the sustainable future

Limited fossil resources and severe environmental problems require new sustainable electricity generation options, which utilize renewable energies and are economical in the meantime. Concentrating solar power (CSP) generation is a proven renewable energy technology and has the potential to become cost-effective in the future, for it produces electricity from the solar radiation. In China, the electricity demand is rapidly increasing, while the solar resources and large wasteland areas are widely available in the western and northern part of China. To change the energy-intensive and environment-burdensome economical development way, Chinese government supports the development of this technology strongly. These factors altogether make China a suitable country for utilizing CSP technology. In this paper, the potential of CSP in China was studied and strategies to promote development of this technology were given.Renewable energy Potential Concentrating solar power China

Building a better bone: The synergy of 2D nanomaterials and 3D printing for bone tissue engineering

Additive manufacturing (AM) is an increasingly important technology for fabricating complex and customized structures using a range of advanced materials and is now playing a critical role in the field of bone tissue engineering (BTE). Two-dimensional nanomaterials (2D NMs) have demonstrated their significance in biomedical science. The convergence of 2D NMs to 3D printing (3DP) technology to create the desired bone scaffolds has become an alternative approach to breakthrough bottlenecks of remaining challenges in BTE, which can potentially achieve the multifunctionality of a bone substitute. The first part of this review provides an overview of the mechanism and critical comparison of the commonly-used 3DP and bioprinting methods. Each method's strengths and weaknesses are evaluated to provide a comprehensive understanding of the current state and for future development. Next, the general synthetic approach to produce 2D NMs, including the top-down and bottom-up approaches, is summarized. Furthermore, an in-depth coverage of the recent advances in combining various 2D NMs with specific 3D printing techniques for bone regeneration is covered. By examining the latest research in this field, this study aims to shed light on the potential of 2D NMs and 3DP technology to revolutionize the field of bone regeneration

Association of depression with hypertensive left ventricular hypertrophy in age, sex, and education level‐specific differences

Abstract Previous studies have shown that hypertension and depression are associated with worse cardiovascular outcomes and reduced quality of life. Left ventricular hypertrophy (LVH) is strongly linked to increased mortality and cardiovascular disease, and depression may be one of the key factors contributing to hypertensive LVH. The authors consecutively enrolled 353 patients with uncomplicated hypertension between November 2017 and May 2021. All participants completed the Hamilton Depression Scale (HAM‐D) to assess their depression status, with depression defined as a HAM‐D score of 20 or higher. Linear regression analysis revealed a positive association between HAM‐D and LVMI (adjusted β, 1.51, 95% CI, 1.19–1.83, p < .001). Logistic regression models showed that individuals with hypertension and depression had a higher risk of LVH than those with hypertension alone (adjusted OR, 2.51, 95% CI, 1.14–5.52, p = .022). The association between depression and LVH significantly interacted with age, sex, education levels, but not BMI and household income. Following age, sex, and education levels stratification, an independent association of depression and LVH was observed only in age <60 years (age <60 years: OR, 7.36, 95% CI, 2.25–24.13, p < .001), male (male: OR, 16.16, 95% CI, 3.80–68.73, p < .001), and higher education levels (high school and above: OR, 11.09, 95% CI, 2.91–42.22, p < .001). Our findings suggest that depression is a significant risk factor for LVH in hypertensive patients, particularly in those who are under 60 years of age, male, and have higher education levels

Association between life’s essential 8 and biological ageing among US adults

Abstract Background Biological ageing is tightly linked to cardiovascular disease (CVD). We aimed to investigate the relationship between Life’s Essential 8 (LE8), a currently updated measure of cardiovascular health (CVH), and biological ageing. Methods This cross-sectional study selected adults ≥ 20 years of age from the 2005–2010 National Health and Nutrition Examination Survey. LE8 scores (range 0–100) were obtained from measurements based on American Heart Association definitions, divided into health behavior and health factor scores. Biological ageing was assessed by different methods including phenotypic age, phenotypic age acceleration (PhenoAgeAccel), biological age and biological age acceleration (BioAgeAccel). Correlations were analyzed by weighted linear regression and restricted cubic spline models. Results Of the 11,729 participants included, the mean age was 47.41 ± 0.36 years and 5983 (51.01%) were female. The mean phenotypic and biological ages were 42.96 ± 0.41 and 46.75 ± 0.39 years, respectively, and the mean LE8 score was 67.71 ± 0.35. After adjusting for potential confounders, higher LE8 scores were associated with lower phenotypic age, biological age, PhenoAgeAccel, and BioAgeAccel, with nonlinear dose–response relationships. Negative associations were also found between health behavior and health factor scores and biological ageing, and were stronger for health factors. In health factor-specific analyses, the β negativity was greater for blood glucose and blood pressure. The inverse correlations of LE8 scores with phenotypic age and biological age in the stratified analyses remained solid across strata. Conclusions LE8 and its subscale scores were strongly negatively related to biological ageing. Encouraging optimal CVH levels may be advantageous in preventing and slowing down ageing