Biochar synthesis from mineral and ash-rich waste biomass, part 2

characterization of biochar and co-pyrolysis mechanism for carbon sequestration

authored by

Rahul Ramesh Nair, Patrick A. Kißling, Alexander Marchanka, Jacek Lecinski, Ariel E. Turcios, Madina Shamsuyeva, Nishanthi Rajendiran, Sathish Ganesan, Shanmugham Venkatachalam Srinivasan, Jutta Papenbrock, Dirk Weichgrebe

Abstract

The increase in mineral and ash-rich waste biomass (MWB) generation in emerging economies poses critical environmental problems and bottlenecks the solid waste and wastewater treatment systems. Transforming these MWB such as sewage sludge from wastewater treatment (SSW) to biochar can be a sustainable method for their disposal and resource recovery. However, such biochar has limited applicability due to the relatively low organic content and possibly contaminated nature of SSW. This may be offset through combined pyrolysis with other MWB, which can also support municipal solid waste management. Studies on this MWB co-pyrolysis are lacking and have not yet seen successful long-term implementation. This work is the second part of authors’ research encompassing an analytical and lab-scale investigation of biochar production from MWB through pyrolysis for the case of Chennai city, India. Here, the physicochemical properties of biochar derived from lab-scale co-pyrolysis of SSW with other MWB such as anaerobic digestate from waste to energy plants of food, kitchen or market waste fermentation, and banana peduncles (BP) collected from vegetable markets and their thermolysis mechanism are comprehensively investigated for purpose of carbon sequestration. Also, a novel preliminary investigation of the effect of sample weight (scaling effect) on the analytical pyrolysis of biomass (BP as model substrate) is undertaken to elucidate its impact on the heat of pyrolysis and carbon distribution in resultant biochar. The maximum carbon sequestration potential of the derived biochar types is 0.22 kg CO₂ kg⁻¹ biomass. The co-pyrolysis of MWB is exothermic and governed by the synergetic effects of the components in blends with emission profiles following the order CO₂ > CH₄ > CO > NH₃. Co-pyrolysis reduced the heavy metal enrichment in SSW biochar. The derived biochars can be an immediate source of N, P and S in nutrient-deficient acidic soils. The biochar has only up to 4-ring polyaromatic compounds and a residence time longer than 1 h at 500 °C is necessary to improve carbonization. The heat released during analytical pyrolysis of the model biomass and distribution of carbon in the resultant biochar are significantly influenced by scaling effects, drawing attention to the need for a more detailed scaling investigation of biomass pyrolysis.

Organisation(s)

Institute of Physical Chemistry and Electrochemistry
Institute of Organic Chemistry
Institute of Plastics and Circular Economy
Institute of Botany
Institute of Sanitary Engineering and Waste Management

External Organisation(s)

Central Leather Research Institute

Type

Article

Journal

Sustainable Environment Research

Volume

33

Publication date

12.2023

Publication status

Published

Peer reviewed

Yes

ASJC Scopus subject areas

Environmental Engineering, Renewable Energy, Sustainability and the Environment, Water Science and Technology, Waste Management and Disposal, Pollution

Sustainable Development Goals

SDG 7 - Affordable and Clean Energy, SDG 11 - Sustainable Cities and Communities, SDG 12 - Responsible Consumption and Production

Electronic version(s)

https://doi.org/10.1186/s42834-023-00176-9 (Access: Open)