With more and more news reports about global warming, air, water, and soil pollution, as well as the increasing pressure on the safety environment and food supply of the growing population, environmental science and sanitation are receiving more and more attention.

With the increasing global awareness of environmental and safety issues, we not only recognize the need to take proactive measures to prevent environmental pollution and protect public health, but also to correct some erroneous decisions made decades ago. Today we thank those who help clean up polluted air and water, purify soil, and meet the demand for replacing hazardous chemicals in our surroundings such as toys, clothing, cosmetics, skincare products, and food.

In these fields, the interaction of nanomaterials plays a crucial role, and a deeper understanding of this field will make important contributions to characterization, evaluation, prediction, and risk control - in ensuring future health and safety and eliminating past pollution.

[Environmental/Nanotoxicology]

Nowadays, nanoparticles are everywhere around us. These tiny particles have already entered products such as sunscreen, food packaging, pharmaceuticals, clothing, and coatings, and are constantly entering new fields. However, the potential risks of intentionally and unintentionally exposing nanoparticles have not been fully evaluated. This has also attracted more attention to nanotoxicology

Nanotechnology is a relatively new scientific field that utilizes the fact that material properties change as size shrinks from macroscopic to nanoscale. The ideal performance of engineering nanomaterials has been applied in many different fields, and they are constantly searching for new application methods. Not only is the use and dissemination of nanomaterials increasing, but nanoscale objects may also experience side effects such as combustion and mechanical wear.

The result is the continuous expansion and release of nanomaterials in our surrounding environment, which increases the exposure of nanoparticles. However, these satisfying new material properties are accompanied by unknown aspects. People often do not know how these particles interact and behave throughout their entire lifecycle. A significant amount of energy and resources are focused on nanotoxicology to assess the effects of intentional and unintentional exposure to nanomaterials, in order to ensure their safety for both humans and the environment.

Characterizing the interaction between nanoparticles and their surrounding environment

Understanding the behavior of nanoparticles in exposed environments is crucial in nanosafety assessments. They need to conduct research in relevant biological environments where the interactions between nanoparticles and the molecules they encounter throughout their entire lifecycle can be monitored. The essence of the interaction with the surrounding environment depends on the nanoparticle material, size, surface charge and functionalization, as well as the surrounding environment such as pH. After the release of nanoparticles, they begin to adsorb organic and inorganic materials, forming a new interface called corona or bioelectron layer, thereby endowing the environment with new characteristics. QSense QCM-D can study such interactions between nanoparticles and the surrounding environment, for example, in this study, the biocompatibility of nanoparticles in the human digestive system was evaluated. This blog post also reviewed several examples of interactions with nanoparticles in relevant contexts. The effect of nanoparticles on phospholipid membranes has also been successfully studied using Langmuir troughs.

[Purification of Environment/Water and Soil]

Water and soil are the two essential elements needed to ensure the health and well-being of humans and other living beings on this planet. These two fields not only provide an environment for our survival and development, but healthy soil and clean water are prerequisites for ensuring the food chain for us and future generations. However, today, environmental pollution of water and soil is receiving increasing attention.

Environmental pollution is man-made and originates from a series of sources. Industry releases toxic by-products and polluted wastewater, while agricultural fertilizers and pesticides infiltrate underground. Other sources include untreated sewage, oil spills, radioactive pollution, and acid rain, all of which pose a threat to human health. As we witness population growth and global wealth growth, we also witness the degradation of these two most important natural resources. The increasing number of people in the world and the high consumption lifestyle caused by more people are putting pressure on the available resources to support growing consumption and constantly changing consumption habits. In order to meet consumer demand and ensure the supply of healthy soil and clean water, it is necessary to clean up polluted water and soil.

Purification and filtration of water

Clean water is an increasingly scarce resource. The demand for high-quality water is not only to provide drinking water for an increasing number of people on Earth, but also to support the production of food, clothing, and agriculture for high consumption lifestyles. To ensure sustainable water supply for future generations and provide safe habitats for aquatic organisms, we need to improve resource utilization and recycle the water we use. We also need to purify polluted water sources such as rivers, lakes, and oceans. In areas with insufficient freshwater supply, recycling and seawater desalination can provide solutions for consumer demand.

An effective method for treating water pollutants is membrane filtration, which can be used for water recovery, reuse, and seawater desalination. QSense QCM-D can be used for the development and evaluation of filtration membranes, characterizing membrane swelling and filtration performance, such as reverse osmosis membranes for seawater desalination and wastewater treatment, as well as membrane fouling.

soil purification

Soil remediation is the process of removing or purifying contaminated soil using different methods. Bioremediation is one of the most meaningful methods for soil purification. In bioremediation, microorganisms are used to decompose pollutants in soil. Bioremediation is commonly used to treat organic pollutants such as petroleum and petroleum based fuels.

The main challenge of bioremediation is the availability of pollutants, as these hydrophobic compounds bind to soil particles and have low solubility in water. In order to enhance the contact between pollutants and microorganisms for degradation, surfactants are generally used. Surfactants can be used to enhance the desorption and solubility of petroleum hydrocarbons, thereby promoting their assimilation by microorganisms.

Most commercially available surfactants are synthesized from petroleum by-products. However, an increasing number of environmental issues have led to the development of alternative natural surfactants to replace existing products. These biosurfactants are typically polymers of glycolipids, lipoproteins, phospholipids, fatty acids, or their chemical properties. At low concentrations, biosurfactants are soluble in water, but at higher concentrations, they form micelles. The point at which micelles form is called the critical micelle concentration (CMC) point. The critical micelle concentration of biological surfactant solutions is usually measured, as the dissolution of petroleum hydrocarbons typically occurs above CMC. From an economic and environmental perspective, it is important to use minimal amounts of surfactants as much as possible.

[Environment/Carbon Storage]

With the increasing attention paid to global warming and its impact on the Earth, the storage of greenhouse gases (mainly carbon dioxide) has become a topic of many research groups. Safely capturing carbon dioxide and storing it in deep saline alkali aquifers is considered a feasible means of controlling carbon emissions into the atmosphere.

One potential underground system for geological storage involves deep saline alkali aquifers. In order to successfully achieve carbon dioxide sequestration, it is necessary to ensure long-term capture of carbon dioxide. This requires an understanding of all physical and chemical capture mechanisms that can preserve carbon dioxide. Capturing carbon dioxide under impermeable sealing layers or fixing carbon dioxide in the pores of aquifers has the greatest and most direct impact. The effectiveness of the two capture mechanisms depends on capillary pressure, therefore the interfacial tension properties between carbon dioxide saltwater and carbon dioxide rock play an important role. Understanding these interactions requires measurement under high temperature and high pressure to simulate water storage conditions.

CO2 saltwater (rock) interaction under high pressure

The functional relationship between interfacial tension of CO2 saltwater and pressure, temperature, salt composition, and concentration was studied. Figure 1 shows typical interfacial tension measurement data, which shows that the interfacial tension value reaches equilibrium at a pressure of around 120 bar.

The functional relationship between interfacial tension (35000 ppm) and pressure (45 ° C) between CO2 water and CO2 saline solution

Wettability is typically defined as the tendency of a fluid to spread and adhere to a solid surface in the presence of another incompatible fluid. In the case of aquifers, it is necessary to consider the saltwater carbon dioxide rock system. If the rock is wet with water, saltwater will occupy the small pores and come into contact with most of the rock. Similarly, if the injected CO2 eventually wets the rock, it will occupy the small pores and come into contact with most of the rock. Study the changes in wettability by measuring the contact angle of CO2 on mineral surfaces in saltwater under high pressure and high temperature.

[Assessment of Environmental/Biological Pollution and Biofilms]

Biological pollution and biofilm formation outside of naturally occurring ecosystems are a hazard. The accumulation of bacterial colonies (usually in industrial environments) can degrade underlying materials, causing corrosion and material failure.

This will result in production losses and increased costs. In addition, it can also pose health risks, such as reducing the performance of filtration membranes, affecting membrane flux, and thus affecting the quality of drinking water.

Biofilms are abundant as part of larger ecosystems, but these microbial bundles can also survive and reproduce in artificial buildings that provide a moist and nutritious environment for microorganisms. Wastewater runoff, production facilities using water-cooled pipelines, other pipeline systems (such as water or oil pipelines), and membrane systems such as membrane bioreactors and reverse osmosis membranes used for wastewater filtration are often affected. The cost of losses caused by biological pollution is enormous, and the consequences of risks to human life and health are very serious. Therefore, understanding and preventing the phenomenon of biological pollution is very meaningful.

Characterization of biological pollution, biofilm formation, and anti fouling coatings

Biofilm is the main obstacle to the effectiveness of membrane and filtration processes. For example, one of the most important factors affecting the performance of membrane bioreactors is membrane fouling caused by extracellular polymeric substances secreted by microorganisms. Although membrane cleaning has been widely studied, methods to prevent contamination are more attractive. Therefore, it is meaningful to understand and characterize how to minimize and prevent pollution and biofilm formation conditions in order to ensure optimal long-term performance of the membrane. Information that helps to better understand the relationship between membrane surface characteristics and fouling tendency can be collected by measuring bacterial adhesion and growth using QSense QCM-D, a technique that can be used to characterize fouling and fouling processes, as well as detect biofilm formation. This technology can also be used to evaluate scale inhibitors and anti fouling solutions, as well as to assist in the design of anti fouling film coatings.

Contact angle for membrane characterization

Membrane fouling is caused by impurities such as inorganic substances (salts, precipitates such as metal hydroxides and carbonates), organic substances, colloids (suspended particles such as silica), microbial contaminants, and particles blocking the pores on the membrane surface or formed by block like substances. Due to the hydrophobic nature of most pollutants, it is generally believed that hydrophilic membranes are required. Using different types of coatings and surface treatments can make the membrane more hydrophilic. Contact angle measurement is commonly used to evaluate surface hydrophilicity.

[Environment/Ink Removal]

De ink is an industrial process that removes ink from recycled paper fibers to produce de ink paper.

The flotation process in de ink

Foam flotation is a common deinking process. It originates from the flotation process commonly used in mining industry. The principle of flotation process is simple: in the flotation tank, small bubbles are dispersed in the pulp. Bubbles will rise and gather hydrophobic ink particles. Therefore, ink particles are lifted to the top of the oil tank to be selected, and the de ink pulp is collected from the bottom of the tank.

Dispersed bubbles play a crucial role in this process. Their properties are strongly influenced by the composition of the fluid medium composed of water and flotation reagents, such as foaming agents, collectors, inhibitors, etc. Among all these reagents, foaming agents are surface active substances that affect the formation and behavior of bubbles. Bubbling molecules adsorb onto the surface of bubbles to form an adsorption layer. During the adsorption process, the surface tension decreases until it reaches the equilibrium value. The kinetics of adsorption and desorption of surfactants from solution under dynamic conditions have a significant impact on bubble behavior. Understanding the rheological properties of the adsorption layer is important for characterizing commercial surfactants.

Download Application Digest: Application of Oscillatory Droplet Technology in Characterizing Surfactant Behavior during Flotation Process.