05/29/2023 | Environmental | 8 MINUTE READ

Accurate pH critical for Tech that Eliminates Dye and Pollutants with Ease!

dye industry

Recently, a new technique for purifying contaminated water has been developed by researchers in Sweden. This technique may be capable of eliminating dye and other pollutants in water with ease. In countries that currently have substandard water treatment facilities and technologies in place, this new technology could be the solution for these problems. It might also be capable of eliminating the widespread issue of toxic dye discharge within the textile industry.

Because of regulations set by the Environmental Protection Agency (EPA), industrial facilities are tasked with reducing the amount of contaminants present in their wastewater. However, some contaminants can’t be effectively removed from effluent with current water treatment solutions. The following article allows you to discover the latest water treatment technology that should benefit many industries and the environment itself.


New Tech for Removing Dye and Other Pollutants from Wastewater

A group of researchers at the Chalmers University of Technology in Sweden have created an entirely new method for filtering and purifying contaminated water via a cellulose-based material. The study of this technology was published in the Industrial & Engineering Chemistry Research scientific journal. In this study, researchers displayed how hazardous dyes are able to be effectively filtered out of wastewater with the material and method that the group has created.

The researchers at Chalmers University use cellulose nanocrystals to help with purification. These particles have an extremely high adsorption ability, which the researchers cultivated to develop a bio-based material that can be adapted and modified depending on the exact types of contaminants that need to be removed from the water.

Unlike other types of treatment, this technique doesn’t use heat or pressure to get rid of contaminants. Instead, it uses sunlight to effectively catalyze the process. When the contaminated water is sent through the cellulose filter, all pollutants are absorbed. At the same time, the sunlight that’s entering the treatment system will break these contaminants down in an efficient manner. This solution is cost-effective and should be easy to install in any facility. The group at Chalmers University is also looking into the possibility of purifying antibiotic residues with the technique.

At North Carolina State University, researchers have also created a new method for getting rid of dyes in wastewater. They use a different process known as “surface modification” in order to create a type of material that’s able to remove all dye pollutants from the water.

These researchers created a synthetic polymer known as polycarbodiimide. They then tested the polymer’s ability to purify wastewater by first dissolving the material in a solvent before mixing it with the water that was contaminated with dyes. During this testing, the solution was placed in water with 20 different anionic dyes. These dyes are commonly used in textile facilities. The initial evaluation involved a visual test to determine if the polymer was working. Further examination was aimed at identifying how effective the polymer was at removing the dye through the use of UV-Vis spectroscopy.

When the polymer solution is mixed with the contaminated water, the polymer is able to attach to the dye, which makes it easy to separated the contaminated mixture from the clean water. This scenario is similar to what occurs when oil is added to water. Of the 20 acidic dyes that were tested, 16 of them were removed. The polymer was then able to be recovered in a matter of minutes. Researchers were also able to deduce why some dyes were removed and others weren’t.


Industries that Create Dye Pollution

In the mining, metal, and leather industries, pollutants from toxic hexavalent chromium commonly occur in wastewater. It’s believed that a cellulose-based material would be able to remove these pollutants from wastewater. Today, there are numerous industries that create dye pollution. The reason why the latest discoveries are highly beneficial is because of how toxic dye pollutants can be.

These pollutants are able to cause skin damage in the event of direct contact. They also increase the risk of organ damage and cancer when they get into the food chain. Nature can also be impacted in a few ways. For instance, high levels of dye in bodies of water can impair the photosynthesis process and result in worse plant growth. Each industry differs in how it creates dye pollution.

Textile and Apparel Manufacturing

The textile manufacturing industry produces more dye pollution than any other industry. Most of the water that’s used to produce clothing is used throughout the dyeing stage of the process.

Post-production water can consist of chemicals, microfibers, residual dye, and mordants. This water is often sent into water streams without being treated. Some textile facilities use pipes that can’t be traced back to them, which ensures that they are able to send contaminated water into the environment without any consequences. These dyes don’t break down once they get into oceans and rivers, which is why this new technology is essential.

Leather and Tanning Industry

The leather and tanning industry uses a considerable amount of chemicals when converting a raw hide into leather. Among the most commonly used chemicals is dye. The issue with this process is that leather doesn’t fully absorb the chemicals, which results in them seeping into the tannery wastewater. The main culprit behind dye pollution in this industry is black dye.

Paper and Pulp Manufacturing

Pigments and dyes have been used in paper and pulp manufacturing for centuries. Along with standard writing paper, there are numerous varieties and grades of paper that go through the dyeing process, the primary of which include:

  • Facial tissue paper
  • Cover papers
  • Copier papers
  • Envelope grades
  • Specialty papers
  • Corrugated cases

While there are numerous dyes that are used in this industry, the main ones include sulfur and cationic dyes. Direct black 22 is among the most commonly used ones. During the production process, some of the dye residue will get into the wastewater. If the water isn’t treated, it will be sent into the environment.

paper making

Printing Industry

The printing industry uses a substantial sum of water and dye during the manufacturing process. It’s common for inks to use dyes or a similar colorant, which is why the printing industry is a leading source of dye pollution. Any wastewater that’s produced from the printing process will contain some dye, which is largely the result of the inefficiency of the dyeing process. Because traditional treatment methods aren’t effective at removing dyes from wastewater, they will harm the environment.

Paint and Coatings Manufacturing

Many modern acrylic paints use dyes to produce new colors or replace certain toxic pigments. During the production process, dyes are dispersed and mixed with other components before being formed into paint. This process uses large quantities of water, after which the resulting wastewater contains high concentrations of dye contaminants.

Plastic Manufacturing

Colorants are routinely added when producing plastic products in different colors. Whether using internal coloring or external coloring, the plastic manufacturing process creates wastewater when the plastic materials are treated. This wastewater contains dyes and other colorants.

Food Industry

Dye is regularly used in the food industry and is especially prevalent in food coloring. These dyes are often placed in fruit, cheese, fish, meat, and other foods that people consume. They are used to preserve freshness and improve aesthetics. When you buy apples or cheese, the color of this food gives you an idea of what it will taste like, what its flavor will be, and how fresh it is. Fruits are regularly dyed to be more visually appealing. In fact, ripe oranges are often green but will be dyed to meet customer expectations.

Just like the other industries on this list, dyes will get into the wastewater and effluent that are produced during the production process. The dye effluents are then discharged into the surrounding waters.

Importance of Accurate pH Readings

Once you’ve determined that you need to remove dyes or other contaminants from your water, it’s essential that you use accurate pH sensors, which is the only way to perform effective water treatment. The method that’s used at the Chalmers University of Technology requires wholly accurate pH readings to properly remove dyes from the water.

During the process, the water’s pH will affect the way that the material interacts with nearby dye pollutants. As for the team at North Carolina State University, they note that pH levels must be accurately controlled throughout the surface modification process.

accurate pH


The textile, leather, mining and metal industries are major contributors to dye pollution in wastewater. New technologies, such as the ones developed at NC State University and Chalmers University of Technology, offer hope in addressing this issue by delivering simple and cost-effective systems to purify contaminated water and separate clean water from the dye pollutants.

These methods are designed to use cellulose-based materials and rely on precise pH readings to effectively remove pollutants. The potential to discover great water purification opportunities with these materials is immeasurable, which is why continued research in the area is critical to solving the global challenges associated with limited access to clean water.

While these technologies continue to evolve and become more effective, they have the potential to provide ample benefits to environmental sustainability, economic development, and human health.

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Posted by Dominic O'Donnell on May 29, 2023

Sensorex is a global leader in the design and manufacture of quality sensors for water quality and process applications. The company offers more than 2000 sensor packages for pH, ORP, conductivity, dissolved oxygen, free chlorine, chlorine dioxide, UV transmittance and other specialty measurements, as well as a full line of sensor accessories and transmitters. Its expert technical support engineers solve analytical sensor challenges with custom designs and off the shelf products.

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