Biochar production potential of Pakistan and its High-value applications

Abstract

Biomass is an abundantly available source of green energy. Biochar is a carbon-rich material derived from a wide variety of organic biomass feedstocks via a thermochemical pathway. Biochar possesses a range of surface area and porosity depending upon the nature of feedstock and pyrolysis conditions, which makes it applicable in multiple dimensions including soil conditioning and high-value product formation. Biochar production from three different waste source including Pine needle, and sewage sludge its application for soil enhancement have been observed, low temperature biochar along with compost, organic fertilizer in the form of manure and microalgal biomass may interact with soil chemistry and plant growth to impact nutrient loss and compensate the hazardous effect of chemical fertilizer and macadamia nutshell and its application for soil conditioning. Similarly, Macadamia nutshell-derived biochar and high-temperature biochar have been used in various applications but the comparison of retort kiln and Top lid-updraft gasifier and the use of two types of designed biochar in soil conditioning and supercapacitor design formation has not been investigated yet. This study elaborates comparison of two biochar production units operating at 400oC (Retort kiln) and 500oC (Top lid-up gasifier), biochar production carried out using agricultural bio-waste and municipal solid waste in a Retort kiln gasifier operating at 400oC and from Macadamia nutshells in a Top lid up-draft gasifier operating at 500oC and characterized using ultimate and proximate analysis to get designed biochar. application of sewage sludge and pine needle biochar produced at 400oC in an application rate of 5% w/w and 10 t h-1 in combination with compost, manure and microalgal biomasses of Closteriopsis acicularis (BM1) and Tetradesmus nygaardi (BM2) on the growth of Chickpea (Cicer arietinum) and Fenugreek (Trigonella foenum-graecum) crop assessed in a pot experiment over a two crop (Chickpea - Fenugreek) cycle in Pakistan. Results depict that the pine needle biochar with additives has increased plant height by 104.1±2.76 cm and fresh biomass by 49.9±1.02g, buffered the soil pH to 6.5 for optimum growth of crops and enhanced carbon retention by 36%. To get designed biochar for high-value application the biochar samples have been steam activated at 950oC. The resultant steam-activated biochar samples show increased and variable surface area DRSML QAU

15 Biochar Production potential of Pakistan and its high value applications and pore size values. For supercapacitor design, Pellet formation is observed best in biochar produced at 500oC in TLUD gasifier. The value of lowest resistance in the case of Coconut biochar BCS500 is promising to use as a temperature sensor. This study highlights the valorization of sewage sludge and pine needle into biochar and the effect of biochar augmentation, its impact on soil nutrients, and plant biomass enhancement. The greener approach also mitigates and helps in the sustainable management of solid wastes. Meanwhile, the optimization towards biochar production to get an efficient but economically best gasifier for pilot scale biochar production and use of high surface area and pore size containing biochar to generate supercapacitors.