Novel approach to mitigating chromium contamination in wastewater

Reduction by reduction: Novel approach to mitigating chromium contamination in wastewater
Chromium contamination in wastewater can be mitigated by converting Cr(VI) to Cr(III) through a photochemical reaction involving copper complexes. Credit: Takashiro Akitsu, Tokyo University of Science

The element chromium, despite having various applications, has a bad reputation. This is because exposure to chromium compounds leads to a higher risk of respiratory cancer and other damaging effects on human health. To add to this problem, chromium also happens to be a major contributor to water pollution due to its presence in industrial waste.

There is, however, a silver lining. As chemists have observed, the toxicity of chromium is dependent on its valence state (a state that is dictated by the number of electrons in the outer shell of an atom). Of the two stable states that chromium exhibits, hexavalent chromium or Cr(VI) and trivalent chromium Cr(III), the former is more toxic and soluble. Thus, chromium contamination can be mitigated by simply converting Cr(VI) to Cr(III) via a process called reduction. Unfortunately, most approaches involved in reducing Cr(VI) to Cr(III) are either expensive and hazardous or have high energy requirements.

To this end, researchers have been focusing on the development of photocatalysts, materials that can facilitate the reduction of harmful substances in the presence of light. The trick is to develop such a reaction using water as the solvent (as opposed to previously used organic solvents), such that they can be directly used to treat wastewater.

A team of researchers, led by Prof Takashiro Akitsu of Tokyo University of Science, has successfully done this, in a recent study published in New Journal of Chemistry. The team also included Yoshito Miyagawa, Tomoyuki Haraguchi (Tokyo University of Science, Japan), Arshak Tsatsuryan (University of Turin, Italy, and Southern Federal University, Russia), and Igor Shcherbakov (Southern Federal University, Russia). Prof Akitsu explains, “In our study, we developed a method to reduce Cr(VI) via light irradiation. We then applied it to an aqueous solvent to make its application easier.”

In their study, the team synthesized copper (Cu(II)) complexes from a range of organic compounds. Through further analyses, they confirmed that these complexes, along with a photocatalyst called titanium oxide (TiO2), are involved in a photochemical reaction leading to the reduction of Cr(VI) in both methanol and water. Specifically, the group studied how the photocatalytic activity of the Cu(II) complex in methanol depended on the wavelength of incident light, while that of the Cu(II) complex with TiO2 in aqueous solution depended on the pH of the solution.

The findings revealed that, on one hand, the rate of Cr(VI) reduction in Cu(II)-methanol photochemical reaction is maximum for visible light in the wavelength range 460-495 nm. On the other hand, Cr(VI) reduction by the Cu(II)-TiO2 system under UV light was found to depend on the pH level of the aqueous solution, exhibiting high reduction efficiencies for acidic solutions with pH values

The study holds promise for the development of a novel wastewater treatment procedure that is both cost-effective and efficient. As Prof Akitsu puts

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AFCO Announces an Exclusive Distribution Agreement with Nuvoda to Expand Wastewater Treatment Offerings to Food and Beverage Processors in the U.S.

Includes Innovative Mobile Organic Biofilm (MOBTM) Technology Allowing for Greater Wastewater Treatment Capacity at a Lower Energy Cost for Customers

AFCO, a Zep Company, announced an exclusive supply agreement with Nuvoda, a leader in innovative solutions in water and wastewater treatment, delivering sustainable, renewable technologies.

AFCO, a leading food safety and biosecurity specialty chemical company, will provide Nuvoda’s award winning MOBTM (Mobile Organic Biofilm) process to Food & Beverage customers and other stakeholders across the U.S. The MOBTM process is a novel, organic and sustainable wastewater treatment innovation that improves settleability and increases treatment capacity, while delivering enhanced nutrient removal and process stability.

“Wastewater treatment that delivers high quality effluent is critical for AFCO’s customers, making Nuvoda’s innovation and expertise an excellent complement to AFCO’s existing cleaning, sanitation, and water treatment solutions,” said Todd Cornwell, Vice President of AFCO Water Group. “The partnership with Nuvoda will strengthen our offerings by providing innovative products to our customers and ensure these facilities are emitting cleaner water.”

Nuvoda has a strong track record of solving complex wastewater problems through innovation and industry expertise. The company’s MOBTM technology is an award-winning, robust, microbiological approach proven to be an effective treatment for industrial wastewater, while minimizing negative impacts of sanitizer chemistry. Most notably, the MOB™ technology can be easily retrofitted into plants that were not originally designed for microbiological treatment, a significant advantage over existing wastewater treatment options and mitigates the need for a large capital investment.

“At Nuvoda, we focus on research and development of technologies that are renewable, minimize environmental impact, and reduce energy consumption, while allowing our customers to meet all of their effluent permits,” said Jason Calhoun, Chief Technology Officer of Nuvoda. “Because we share this same mission, we’re excited to welcome AFCO as an ongoing partner after working together for the past five years, to deliver superior support and cutting-edge technologies for our customers in the food and beverage market.”

AFCO/Nuvoda has a team of highly qualified field sales personnel that can assess new or existing customers’ wastewater treatment programs via a pilot plant test. Interested clients can reach out to our sales team at [email protected] for additional information.

About AFCO

AFCO, a Zep Company, focuses on food safety through local SQF & HACCP-educated Reps who provide technical service and support through the Assure™ Sanitation Program. AFCO offers high-quality food industry cleaners and sanitizers, antimicrobial intervention, biofilm removers, equipment systems, and more. Zep Inc. is a premium global industrial specialty chemicals producer serving business-to-business and select consumer markets. Zep’s product portfolio includes anti-bacterial and industrial hand care products, sanitizers, cleaners, degreasers, deodorizers, disinfectants, automotive appearance and maintenance chemicals, floor finishes, and pest and weed control products. Zep is headquartered in Atlanta, GA.

About Nuvoda

Nuvoda is a leader in innovative solutions in water and wastewater treatment delivering sustainable, renewable technologies geared directly toward increasing capacity and lowering costs. The company is headquartered in Raleigh, NC, with research and manufacturing centers in Blacksburg, VA

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