Electrochemical sensors based on sewage sludge–derived biochar for the analysis of anthocyanins in berry fruits

Abstract

The reutilization of waste and the reduction of the general environmental impact of every production are fundamental goals that must be achieved in the framework of a circular economy. Recycled carbon-rich materials may represent a promising alternative to other less-sustainable carbonaceous materials used in the production of electrochemical sensing platforms. Herein, we propose an innovative carbon paste electrode (CPE) composed of biochar derived from biological sludge obtained from municipal and industrial wastewater treatment plants. The physicochemical properties of the biochar after a chemical treatment with an acidic solution obtained from industrial by-products were investigated. The electrode surface characterization was carried out by analyzing common redox probes and multiple phenols bearing varying numbers of –OH and –OCH3 groups in their structure. Furthermore, the CPE was also tested on the evaluation of the phenolic fingerprints of Vaccinium myrtillus, Vaccinium uliginosum subsp. gaultherioides, and Fragaria × ananassa. Standard anthocyanin mixtures and extracts of the aforementioned fruits were analyzed to provide a phenolic characterization of real samples. The obtained results show that the sewage sludge–derived biochar can be a promising material for the development of electroanalytical sensors. Graphical abstract

Biochar for Water Pollution Control: From Sensing to Decontamination

“…The sensor was prepared via the drop-coating technique on the electrode surface, and analyte detection was carried out via SWV stripping analysis. Contrary to statements made in other works [59][60][61], chemical activation via an acidic or alkali medium (nitric acid, sodium hydroxide) was detrimental to the electrochemical response signal in this case. Untreated biochar-modified electrodes showed the highest peak current response to Cd ions.…”

Biomass-Derived Carbon-Based Electrodes for Electrochemical Sensing: A Review

“…In particular, the similarities between some treated recycled carbonaceous materials with carbon black, such as amorphous carbon, containing minimal amounts of oxygen, nitrogen, and hydrogen, represent a low-cost alternative to other carbon-based materials in electrochemical sensing and energetics. In this context, Sfragano et al [ 109 ] proposed an innovative carbon paste electrode composed of biochar derived from biological sludge from municipal and industrial wastewater treatment plants for sensing phenolic compounds. The catalyst was prepared via the pyrolysis of a mixture of waste woody biomass and biological sludge under a N 2 atmosphere at 850 °C for 60 min.…”

“… Differential pulse voltammograms recorded in 0.1 M acetic buffer pH 4.75 at the prepared catalyst for ( a ) 0.1 mM hydroquinone; ( b ) 0.025 mM catechol; ( c ) 0.1 mM gallic acid; ( d ) 0.1 mM resorcinol; ( e ) 0.1 mM vanillin; pulse amplitude 90 mV, pulse width 60 ms, and scan rate 30 mVs −1 [ 109 ]. …”

Biochar: A Sustainable Alternative in the Development of Electrochemical Printed Platforms

“…Other biosensors dealing with biochar-modified CPE and GCE are reported in Table 5. Olive oil [129] Acronyms: Medical Injection (MI), p-Nitrophenol (pNP), Bouganvillea spectabilis flowers (BSF), Furazolidone (FRZ), Nano-powdered Biochar (Nanop-Biochar).…”