Making a Difference for the Planet: art photonics ATR Fiber Optic Probes for Oil-Contaminated Soil Analysis

With #earthmonth upon us, we want to take a moment to reflect on the importance of environmental protection. As a company, we at #artphotonics are committed to developing innovative solutions that can help address environmental challenges. One such challenge is the contamination of soil with oil, which can have severe and long-lasting consequences for the environment.

Oil production and processing generate significant amounts of waste, such as oil sludge, wastewater, and oil-contaminated soil. The natural assimilation of these dangerous oil contaminants by the environment is very slow, and long exposure to oil-containing waste can lead to the migration of hydrocarbons and other harmful components in the environment. This can result in secondary contamination sites that can be very challenging to remediate.

Our company has developed a range of Fiber Optic Probes that can help detect and analyze total hydrocarbons and water in oil-contaminated soils. Our recent study used a sampling-free optical #spectroscopy method of soil analysis, using our Mid-IR #ATR probes, and the results were very promising. Part of our research paid particular attention to the supervised #machinelearning algorithm, allowing to establish a reliable and accurate method for analyzing hydrocarbons and water in oil-contaminated soils using our probes.

In the article, we would like to share some of the key findings from our research and explain how our probes can help address the challenge of oil-contaminated soils. We believe that the combination of highly selective and sensitive Mid-IR spectroscopy with sampling-free measurement through the ATR probe can be put into the basis of a field analytical method. So, stay tuned to learn more about our prototype development of an ATR MIR field analyzer for the determination of hydrocarbons and water in oil-contaminated soils.

Field-Based Monitoring of Oil-Contaminated Soils Using Infrared Spectroscopy

We've all heard about the devastating effects of soil contamination caused by oil development and processing products. It's a global problem that affects our planet's health and ecosystem. That's why we set out to find a way to make the analysis of oil-contaminated soils more efficient and accessible, without compromising accuracy.

Laboratory-based spectroscopy in the mid-IR (MIR) range provides accurate analysis, but it's not efficient enough for ecological monitoring. That's where our research comes in. We investigated the feasibility of using mid-infrared spectroscopy and the Fiber Optic ATR probe (Figure 1) for direct (i.e. without sample preparation) quantitative analysis of total hydrocarbons and water in oil-contaminated soils. Our goal was to find an efficient and cost-effective alternative to time-consuming and expensive lab analysis, with a field application in mind.

Exploratory Study: Spectral Properties of Model Soils

In our exploratory study, we analyzed the spectral properties of pure and oil-contaminated model soils composed of sand, clay, dolomite, and humus. We studied the full MIR range of 4000-400 cm-1, interpreted various soil and oil components, and compared different ATR head materials (Figure 2). Our analysis led us to choose a chalcogenide IR (CIR) fiber-based probe with an ATR element made of Cubic Zirconia crystal, as it corresponds to analysis in the region 4000-1600 cm-1.

Data Analysis and Calibration: Building Calibration Models

Using the art photonics' ATR probe, we analyzed the spectra of 25 design samples containing varying (1-15%) oil and water additions in a typical soil sample. Our results showed that the spectral data could be used to build calibration models for the analysis of hydrocarbon contamination independently of the sample moisture. We also built a water content determination model. We overcame the worse quality of ATR spectra of drier samples and variable spectral intensity inherent with ATR measurement of solids (Figure 3) by using a mathematical data pretreatment. Further improvement of model performance was achieved using variable selection based on genetic algorithms.

Our suggested method allows the determination of oil and water content in soils with high accuracy. Our prediction root mean-square errors, proven by two validation methods, were 1.3% and 0.9% for oil and water content, respectively, which is sufficient for a wide range of practical applications. Our results can be used for the development of a portable device for the hydrocarbons' and water determination in soils, for instance, during their biotechnological remediation. Our method can also be used for the operative monitoring of oil sludge remediation processes under field conditions.

Conclusion

We are proud to have developed a method that's efficient, cost-effective, and accurate. We're excited to see how our results will contribute to a better, healthier planet. While there are technical improvements to be made for environmental monitoring at low contamination levels (below 1% of total hydrocarbons), we believe that our method is a significant step forward in the fight against soil contamination.

Want to learn more? You can access the article here: Quantitative analysis of total hydrocarbons and water in oil‐contaminated soils with attenuated total reflection infrared spectroscopy