Assessment of Physicochemical and Nutritional Characteristics of Waste Mushroom Substrate Biochar under Various Pyrolysis Temperatures and Times

Abstract

The prime objective of biochar production is to contribute to nutrients recycling, reducing waste and converting useful bio-wastes into carbon rich products in the environment. The present study was intended to systematically evaluate the effect of pyrolysis conditions and characteristics of feedstock influencing the generation of biochar. The study revealed the nutritional importance of waste mushroom substrate (WMS) biochar which may elevate soil nutritional status and soil quality. The results showed that the yields and properties of WMS biochar depended principally on the applied temperature where pyrolysis at higher temperatures, that is, 600 °C and 700 °C produced biochar having high ash, P and K contents. Moreover, numerous useful macro and micro nutrients such as Ca, Mg, Fe and Zn were observed to positively correlate with the increase in temperature. The WMS biochar in our study is highly alkaline which can be used to rectify acidic soil pH. Overall our results suggest that WMS biochar being a rich source of nutrients can be the best remedy to maintain and further enhance the soil nutritional status. Thus by interpreting biochar feedstock characteristics and pyrolysis conditions, the regulation of tailored WMS biochar manufacturing and application in soil can be facilitated.

Influence of pyrolysis conditions on the properties and Pb2+ and Cd2+ adsorption potential of tobacco stem biochar

“…In crop residue biochars (wheat straw, rice straw, maize straw, and rice husk), the N content ranged from 8.47 g kg −1 to 16.1 g kg −1 , the P content ranged from 1.67 g kg −1 to 4.43 g kg −1 , and the K content ranged from 12.9 g kg −1 to 32.0 g kg −1 (Bian et al 2016). Similar ranges had been reported in spent mushroom substrate biochars (Sarfraz et al 2019;Zhao et al 2019). A meta-analysis by Ippolito et al (2015) reported an average total concentration of 0.9 g kg −1 to 32.8 g kg −1 for N, an average total concentration of 0.32 g kg −1 to 60.8 g kg −1 for P, and an average total concentration of 0.7 g kg −1 to 116 g kg −1 for K, for a wide range of biochar materials.…”

“…The decrease in total biochar yield as the pyrolysis temperature and holding time were increased could be attributed to the breakdown of the basic primary structure of the biochar during pyrolysis. A decrease in the total biochar yield as the temperature increased had also been reported in oak, pine, sugarcane, and peanut shell biochar (Zhang et al 2015); spent mushroom substrates biochar (Sarfraz et al 2019;Zhao et al 2019); pig manure (Gasco et al 2018); and straw and lignosulfonate (Zhang et al 2015). Previous reports had also shown that feedstock was partially combusted at lower pyrolysis temperatures, which resulted in a higher yield; while a higher temperature resulted in the complete combustion of the biomass (Angin 2013;Ghanim et al 2016) as well as increased gasification (Colantoni et al 2016;, which resulted in a decrease in the total yield.…”

“…Those with different letters are significantly different (p-value was less than 0.05) heavy metal concentrations were well below the thresholds required for the safe usage of the biochar in the environment, and therefore, could be applied to the soil without environmental concerns. Previous studies have shown that the concentration of heavy metals can be greater in the biochar than in the feedstock (Sarfraz et al 2019;Zhao et al 2019). However, biochar is able to effectively bind and immobilize heavy metals for a long period of time, but the length of time is yet to be determined (EBF 2017).…”

Effects of Two Types of Straw Biochar on the Mineralization of Soil Organic Carbon in Farmland

“…The physical and chemical properties of biochar determine the changes in soil properties. Some experimental results show that the yield and characteristics of biochar mainly depend on its pyrolysis temperature and raw materials [18,19].…”

Comparative analysis of nutrients composition in biochar produced from different feedstocks at varying pyrolysis temperature

“…The highest values of 8.38 mg g -1 K content, 16.2 mg g -1 Ca content, 4.21 mg g -1 Mg content, 14.8 % H content and 0.28 % S content at the lowest temperature of 300 o C were found in CD, CC, CC, PL and CC, respectively, with their lowest values found in the highest temperature of 600 o C. The findings is similar to Nwajiaku et al [25] where increase in pyrolysis temperature decreased K and Mg. However, Sarfraz et al [26]; Naeem et al [23] and Gaskin et al [30] reported increase in temperature with increase in K, Ca and Mg contents. Nelissen et al [31] and Al-Wabel et al [32], differently reported decrease in H content and H and S contents respectively with increase in temperature.…”