Understanding metal(loid) chemistry is essential as the toxicity and mobility of each element significantly depend on their chemical species. Metalloids such as arsenic, lead and cadmium, are known as toxic and carcinogenic elements that may cause severe health concerns even at low concentrations. Metalloid removal from water bodies becomes necessary to offer safe environments.
In her doctoral dissertation, MSc(Eng) Suchanya Wongrod focused on the use of biochars, solid char derived from by-product organic waste digestates, as sorbing materials for metal(loid) removal from water. She determined the physical and chemical properties of biochars before and after chemical treatments and investigated the effects of chemical treatments and washing procedures applied to the biochars on the lead, cadmium and arsenic sorption capacity. She further evaluated the evolution and distribution of arsenic redox species during arsenic sorption on the biochars and in solutions.
The sewage sludge digestate and the organic fraction of municipal solid waste digestate are organic by-product remains from wastewater or solid waste treatment. These digestates may be considered as alternative feedstocks for biochar production to promote the recycling of organic wastes and generate added-value bio-products.
“Generally speaking, the digestate-derived biochars have much lower sorption capacities for metalloids compared to activated carbons. That is why chemical treatment is considered a potential option to improve the biochar surface properties and to enhance its sorption ability for metalloids,” Wongrod notes.
Wongrod’s results showed the improved properties of biochars after the chemical treatments in accordance with the enhanced sorption ability for lead, cadmium and arsenic. They also highlight the importance of washing procedures in metalloid sorption, particularly with lead and arsenic.
Key words in English: biochar, metal, sorption, arsenic redox distribution
Key words in Finnish: biohiili, metallit, sorptio, arseenin kemiallinen muoto
The doctoral dissertation of MSc(Eng) Suchanya Wongrod in the field of Environmental Technology titled Biochars from solid digestates as sorbing materials for metal(loid)s removal from water will be publicly examined in the Faculty of Engineering and Natural Sciences at Tampere University at 1:15 pm on Thursday, 23 May 2019 in room FA032 (Pieni sali 1, Hervanta campus, Korkeakoulunkatu 8, Festia, Tampere, Finland). The Opponents will be Professor Silvia Fiore from Politecnico di Torino (Italy), Professor Florence Pannier from Université de Pau et des Pays de l'Adour (France) and Professor Marie-Odile Simonnot from Université de Lorraine (France). The Custos will be Professor Gilles Guibaud from Université de Limoges (France).
Suchanya Wongrod's doctoral research was conducted in the framework of the Advanced Biological Waste to Energy Technologies (ABWET) Innovative Training Network (ITN) European Joint Degree Programme. ABWET has four partner organizations: Université Paris-Est (France), IHE Delft Institute for Water Education (the Netherlands), University of Cassino and Southern Lazio (Italy), and Tampere University (Finland). The Examination Committee of Suchanya Wongrod's doctoral dissertation includes one representative from each partner organization.
Suchanya Wongrod comes from Surat Thani (Thailand) and intends to work as a lecturer/researcher in the field of Environmental Technology/Engineering at the research institutes and/or the universities in Thailand.
The dissertation is available in the Faculty of Engineering and Natural Sciences at Tampere University and by request from suchanya.wongrod [at] gmail.com.
Further information: Suchanya Wongrod, suchanya.wongrod [at] gmail.com
Photo: Ngọc Diệp Nguyễn
Watch the defence online here.