The applicability of steam activated pine and spruce bark biochar for storm water and wastewater purification has been investigated. Biochar samples produced from the bark of scots pine (Pinus sylvestrus) and spruce (Picea spp.) by conventional slow pyrolysis at 475 °C were steam activated at 800 °C. Steam activation was selected as a relatively inexpensive method for creating porous biochar adsorbents from the bark-containing sidestreams of the wood refining industry. A suite of standard analytical procedures were carried out to quantify the performance of the activated biochar in removing both cations and residual organics from aqueous media. Phenol and microplastics retention and cation exchange capacity were employed as key test parameters. Despite relatively low surface areas (200–600 m²/g), the steam-activated biochars were highly suitable adsorbents for the chemical species tested as well as for microplastics removal. The results indicate that ultra-high porosities are not necessary for satisfactory water purification, supporting the economic feasibility of bio-based adsorbent production.

Activated carbons (AC) serve as adsorbents in various applications requiring specific functionalities. In this study, the effects of biomass type, pre-carbonization process, and activation method on the properties of ACs were investigated. Chemical (KOH and H3PO4) and physical (CO2) activations were performed on slow pyrolyzed and hydrothermally carbonized (HTC) biochars produced from two feedstocks, willow and Scots pine bark (SPB). In addition, the adsorption capacities of the ACs were tested with two dyes and zinc metal. Distinct differences were found between the biochars and ACs regarding pore size distributions, surface area (238 – 3505 m2 g-1), and surface chemistry. KOH activation produced highly microporous ACs from all biochars, whereas with H3PO4 and CO2 there was also increase in the meso- and macroporosity with the HTC biochars. Adsorption capacity for dyes was dependent on the surface area, while for zinc it depended on AC’s pH. The results provide interesting insights into tailoring ACs for specific applications.

The conversion of biomass and natural wastes into carbon‐based materials for various applications such as catalysts and energy‐related materials is a fascinating and sustainable approach emerged during recent years. Precursor nature and characteristics are complex, hence, their effect on the properties of resulting materials is still unclear. In this work, we have investigated the effect of different precursors and pyrolysis temperature on the properties of produced carbon materials and their potential application as negative electrode materials in Li‐ion batteries. Three biomasses, lignocellulosic brewery spent grain from a local brewery, catechol‐rich lignin and tannins, were selected for investigations. We show that such end‐product carbon characteristic as functional and elemental composition, porosity, specific surface area, defectiveness level, and morphology strictly depend on the precursor composition, chemical structure, and pyrolysis temperature. The electrochemical characteristics of produced carbon materials correlate with the characteristics of the produced materials. A higher pyrolysis temperature is shown to be favourable for production of carbon material for the Li‐ion battery application in terms of both specific capacity and long‐term cycling stability.

Water reuse from wastewater treatment plants can significantly reduce freshwater demand. Additionally municipal sewage and some industrial wastewaters could be used as sources of nutrients and carbon more effectively than they are used today. Biological treatments have attracted the most attention in wastewater purification, whereas, so far, only a little attention has been paid to the physico-chemical technologies. These technologies could, however, have great potential to recover nutrients when purifying wastewater. In this study, the main emphasis was to study the possibilities to utilize existing physico-chemical unit operations for wastewater purification and nutrients as well as carbon recovery. Unit operations were selected so that they could produce exploitable circular economy products from wastewaters and be assembled in a mobile container for carrying out recovery anywhere that is suitable. The results showed that in a mobile container, solids could be successfully separated from the studied wastewaters by flocculation-assisted solid/liquid separation and then processed into hydrochar by hydrothermal carbonization. Phosphate was precipitated using lime milk as calcium phosphate, and ammonium nitrogen was captured from the wastewater using membrane contactor technology resulting in ammonium sulphate for fertilizer use. Additionally, reverse osmosis retained residual impurities well, producing good quality water for reuse. The techno-economic feasibility seems promising.