3 years ago

Lignin-based activated carbons as metal-free catalysts for the oxidative degradation of 4-nitrophenol in aqueous solution

Lignin-based activated carbons as metal-free catalysts for the oxidative degradation of 4-nitrophenol in aqueous solution
A wheat and hemp lignin, obtained from a soda pulping-precipitation process, was carbonized at 800°C under N2 atmosphere. The resulting carbon material was thermally activated under oxidative atmosphere at four different temperatures (150, 200, 300 and 350°C). The materials prepared at higher activation temperatures (300 and 350°C) have proven their potential in the elimination of 4-nitrophenol (4-NP) from aqueous model solutions (5gL−1) when using catalytic wet peroxide oxidation (CWPO). In these conditions we were able to remove around 70% of 4-NP after 24h, with an efficient H2O2 decomposition, in experiments conducted at relatively mild operating conditions (atmospheric pressure, 50°C, pH=3, catalyst load=2.5gL−1 and [H2O2]0 =17.8gL−1). By increasing the working temperature to 80°C, complete 4-NP removal was obtained within 48h (against 93% 4-NP removal at 50°C), with an efficiency of H2O2 consumption of 70% and a significant mineralization (61%). On the other hand, the materials prepared at lower activation temperatures (150 and 200°C), with higher basicity, promote the faster but inefficient H2O2 decomposition, 4-NP removal being lower than 25% after 24h at 50°C in CWPO. This can be attributed to the formation of species other than HO radicals during H2O2 decomposition, the recombination of the formed radicals into non-reactive species and a poor adsorption capacity.

Publisher URL: www.sciencedirect.com/science

DOI: S0926337317307130

You might also like
Discover & Discuss Important Research

Keeping up-to-date with research can feel impossible, with papers being published faster than you'll ever be able to read them. That's where Researcher comes in: we're simplifying discovery and making important discussions happen. With over 19,000 sources, including peer-reviewed journals, preprints, blogs, universities, podcasts and Live events across 10 research areas, you'll never miss what's important to you. It's like social media, but better. Oh, and we should mention - it's free.

  • Download from Google Play
  • Download from App Store
  • Download from AppInChina

Researcher displays publicly available abstracts and doesn’t host any full article content. If the content is open access, we will direct clicks from the abstracts to the publisher website and display the PDF copy on our platform. Clicks to view the full text will be directed to the publisher website, where only users with subscriptions or access through their institution are able to view the full article.