Characterization and Potential Applications of Hydrochars Derived from P- and N-Enriched Agricultural and Antibiotic Residues via Microwave-Assisted Hydrothermal Conversion

Abstract

The effect of treatment temperature on hydrochars’ properties using P- and N-enriched agricultural and antibiotic residues as feedstocks via microwave-assisted hydrothermal conversion (MW-HTC) was investigated in this study. MW-HTC changed the physicochemical properties of hydrochars, nutrient fractions (phosphorus (P) and nitrogen (N)), and surface functional groups which were characterized by various analysis tools. The N contents in hydrochars derived from rapeseed (RS) and lincomycin (LM) residues were 7.26 and 7.76% at 120 °C, respectively. At 210 °C, those values were reduced to 5.16 and 3.14% accordingly, indicating a higher temperature led to more N release. The speciation of P fractions was affected by temperature, and LM derived hydrochars possessed higher bioavailable P for plants’ nutrient uptake. The atomic ratios of H/C and O/C decreased with treatment temperature for both RS and LM derived hydrochars. LM derived hydrochars were thermally more stable than RS derived hydrochars. RS derived hydrochars exhibited better higher heating value (HHV; 22.0–26.8 MJ/kg) while LM derived hydrochars revealed higher fuel ratio (0.47–0.95). MW-HTC offered a viable route for conversion of P- and N-enriched agricultural and antibiotic residues into highly efficient hydrochars for environment-friendly applications.

Recent advancement of biomass-derived porous carbon based materials for energy and environmental remediation applications

“…161 Likewise, P, N-rich agricultural (rapeseed) and antibiotic (lincomycin) residual feedstocks were used for the preparation of hydrochars via microwave-assisted HTC method for environmental applications. 162…”

“…161 Likewise, P, N-rich agricultural (rapeseed) and antibiotic (lincomycin) residual feedstocks were used for the preparation of hydrochars via microwave-assisted HTC method for environmental applications. 162 The advantages of HTC process over pyrolysis include improved energy consumption, minimized toxic wastes generation, higher yield ($30-60 wt%), retention of surface hydroxyl and carboxylic functional groups and doping of heteroatoms. Even then to meet certain special standards for few applications, template and additive additions are also considered as powerful tools for tuning the pore size ordering and microporosity in the obtained carbon products.…”

Virtual Special Issue of Recent Research Advances in China: Thermochemical Processing of Biomass and Solid Wastes

“…There are four papers on this topic. Ahmad et al . investigate the effect of the treatment temperature on properties of hydrochars using P- and N-enriched agricultural and antibiotic residues as feedstocks via microwave-assisted hydrothermal conversion.…”

“…There are four papers on this topic. Ahmad et al 10 investigate the effect of the treatment temperature on properties of hydrochars using P-and N-enriched agricultural and antibiotic residues as feedstocks via microwave-assisted hydrothermal conversion. Huang et al 11 study the effects of torrefaction pressure on the physicochemical properties and combustion characteristics of torrefied Phragmites australis.…”

Electrochemical Sensor Based on Spent Coffee Grounds Hydrochar and Metal Nanoparticles for Simultaneous Detection of Emerging Contaminants in Natural Water

“…Although hydrochar has a low surface area and porosity, it can be activated and functionalized by several modification methods, such as CO 2 treatment, the use of KOH or sulfonation with concentrated H 2 SO 4 to improve its physicochemical properties [18][19][20][21]. Therefore, this carbonaceous material has a wide range of applications, having been used in wastewater treatment [22], the removal of heavy metals [18,23], soil amendment [24,25] and energy production [18,25,26]. However, despite the growing interest in hydrochar and its applications, very few studies involving its use in electrochemical sensing have been reported in the literature [27].…”