ENV-607: SURFACTANT-MODIFIED BIOMASS ADSORBENTS FOR ENHANCED REMOVAL OF POLLUTANTS FROM AQUEOUS SOLUTION

From the view of economical efficiency and technology sustainability, considerable attention has been recently given to the use of low-cost biomass residues as adsorbents in pollution control. To achieve a desirable adsorptive efficiency, some efforts have also been made to modify biomass adsorbents through appropriate treatments. There is a particular interest in surfactant-assisted biomass surface modification. Although some findings from previous studies are encouraging, knowledge about the adsorption of pollutants onto surfactant-modified biomass is still limited. A number of issues about the characteristics of involved interface transport are poorly understood. The present study therefore aims to examine the adsorption of anionic azo dyes onto surfactant-modified biomass in the solution. Different surfactants are used for modification. The equilibrium and kinetic studies for the adsorption of anionic azo dyes on modified biomass are conducted and the effects of aqueous chemistry characteristics are also evaluated. The results present the potential of modified biomass as suitable adsorbent for the removal of anionic azo dyes from wastewater. It can help understand the migration patterns of organic pollutants at biomass-water interface

Impact of Microplastics on Oil Dispersion Efficiency in the Marine Environment

Oil spill and microplastics (MPs) pollution has raised global concerns, due to the negative impacts on ocean sustainability. Chemical dispersants were widely adopted as oil-spill-treating agents. When MPs exist during oil dispersion, MP/oil-dispersant agglomerates (MODAs) are observed. This study explored how MPs affect oil-dispersion efficiency in oceans. Results showed that, under dispersant-to-oil volumetric ratio (DOR) 1:10 and mixing energy of 200 rpm, the addition of MPs increased the oil droplet size, total oil volume concentration, and oil-dispersion efficiency. Under DOR 1:25 and mixing energy of 120 rpm, the addition of MPs increased the oil droplet size but resulted in a decrease of total oil volume concentration and dispersion efficiency. Compared with the oil volume concentration, the oil droplet size may no longer be an efficient parameter for evaluating oil-dispersion efficiency with the existence of MODAs. A machine learning (ML)-based XGBRegressor model was further constructed to predict how MPs affected oil volume concentration and oil-dispersion efficiency in oceans. The research outputs would facilitate decision-making during oil-spill responses and build a foundation for the risk assessment of oil and MP co-contaminants that is essential for maintaining ocean sustainability

Impact of Microplastics on Oil Dispersion Efficiency in the Marine Environment

Oil spill and microplastics (MPs) pollution has raised global concerns, due to the negative impacts on ocean sustainability. Chemical dispersants were widely adopted as oil-spill-treating agents. When MPs exist during oil dispersion, MP/oil-dispersant agglomerates (MODAs) are observed. This study explored how MPs affect oil-dispersion efficiency in oceans. Results showed that, under dispersant-to-oil volumetric ratio (DOR) 1:10 and mixing energy of 200 rpm, the addition of MPs increased the oil droplet size, total oil volume concentration, and oil-dispersion efficiency. Under DOR 1:25 and mixing energy of 120 rpm, the addition of MPs increased the oil droplet size but resulted in a decrease of total oil volume concentration and dispersion efficiency. Compared with the oil volume concentration, the oil droplet size may no longer be an efficient parameter for evaluating oil-dispersion efficiency with the existence of MODAs. A machine learning (ML)-based XGBRegressor model was further constructed to predict how MPs affected oil volume concentration and oil-dispersion efficiency in oceans. The research outputs would facilitate decision-making during oil-spill responses and build a foundation for the risk assessment of oil and MP co-contaminants that is essential for maintaining ocean sustainability

Insights into toxicity of polychlorinated naphthalenes to multiple human endocrine receptors: Mechanism and health risk analysis

This study explored the combined disruption mechanism of polychlorinated naphthalenes (PCNs) on the three key receptors (estrogen receptor, thyroid receptor, and adrenoceptor) of the human endocrine system. The intensity of PCN endocrine disruption on these receptors was first determined using a molecular docking method. A comprehensive index of PCN endocrine disruption to human was quantified by analytic hierarchy process and fuzzy analysis. The mode of action between PCNs and the receptors was further identified to screen the molecular characteristics influencing PCN endocrine disruption through molecular docking and fractional factorial design. Quantitative structure–activity relationship (QSAR) models were established to investigate the toxic mechanism due to PCN endocrine disruption. The results showed that the lowest occupied orbital energy (ELUMO) was the most important factor contributing to the toxicity of PCNs on the endocrine receptors, followed by the orbital energy difference (ΔE) and positive Millikan charge (q+). Furthermore, the strategies were formulated through adjusting the nutritious diet to reduce health risk for the workers in PCN contaminated sites and the effectiveness and feasibility were assessed by molecular dynamic simulation. The simulation results indicated that the human health risk caused by PCN endocrine disruption could be effectively decreased by nutritional supplementation. The binding ability between PCNs and endocrine receptors significantly declined (up to −16.45%) with the supplementation of vitamins (A, B2, B12, C, and E) and carotene. This study provided the new insights to reveal the toxic mechanism of PCNs on human endocrine systems and the recommendations on nutritional supplements for health risk reduction. The methodology and findings could serve as valuable references for screening of potential endocrine disruptors and developing appropriate strategies for PCN or other persistent organic pollution control and health risk management

The Optimization of Canola Crop Production through Wheat Residue Management within a Western Canadian Context—A Case Study of Saint-Front, Saskatchewan

In this study, the processes of wheat residue degradation in combination with various tillage treatments were explored to determine the ideal management prescription for maximizing canola crop production. A field experiment within a western Canadian context (near Saint-Front, Saskatchewan), consisting of a 2 × 3 factorial design, was conducted to determine the fate of crop residue under different harvest and treatment scenarios. ATR-Fourier transform infrared (FTIR) spectroscopy, FTIR spectromicroscopy, and synchrotron-based X-ray fluorescence imaging (SR-XFI) were used to explore wheat residue degradation mechanisms. The results indicated maximum canola yields and residue degradation occurred in combination with a combine outfitted with an aftermarket chopper and post-harvest treatment by harrow. Crop residue degradation was attributed to cellulose/linen hydrolysis and supramolecular structure changes from high crystalline to amorphous cellulose. Multi-element loss usually accompanied crop residue degradation. An important aspect of this study is the adoption of field-scale analysis to accurately portray real-world sustainable management techniques within a western Canadian context. The findings provided an optimal combination of crop residue treatment and tillage treatment to increase canola production, which had the potential ability to be applied in other countries. It is also an initial attempt to develop a technical composite of FTIR spectromicroscopy and SR-XFI for examining the mechanism of residue decomposition

Insights into the Toxicity of Triclosan to Green Microalga <i>Chlorococcum sp.</i> Using Synchrotron-Based Fourier Transform Infrared Spectromicroscopy: Biophysiological Analyses and Roles of Environmental Factors

This study investigated the toxicity of triclosan to the green microalga <i>Chlorococcum sp.</i> under multiple environmental stressors. The interactions between triclosan and environmental stressors were explored through full two-way factorial, synchrotron-based Fourier transform infrared spectromicroscopy and principal component analyses. Phosphorus concentration, pH * phosphorus concentration, and temperature * pH * NaCl concentration were the most statistically significant factors under triclosan exposure. The variation of those factors would have a huge impact on biophysiological performances. It is interesting to find <i>Chlorococcum</i> sp. may become more resistant against triclosan in phosphorus-enriched environment. Besides, particular significant factors from multiple environmental stressors showed the impacts of triclosan on the corresponding response of <i>Chlorococcum</i> sp. owing to the specific structure and performance of biomolecular components. Moreover, two high-order interactions of temperature * pH * NaCl concentration and temperature * pH * NaCl concentration * phosphorus concentration had more contributions than others at the subcellular level, which could be attributed to the interactive complexity of biomolecular components. Due to cellular self-regulation mechanism and short exposure time, the biophysiological changes of <i>Chlorococcum sp.</i> were undramatic. These findings can help reveal the interactive complexity among triclosan and multiple environmental stressors. It is suggested that multiple environmental stressors should be considered during ecological risk assessment and management of emerging pollutants