Characterization of dissolved organic matter in biochar derived from various macroalgae (Phaeophyta, Rhodophyta, and Chlorophyta): Effects of pyrolysis temperature and extraction solution pH

Effect of pyrolysis temperature and molecular weight on characterization of biochar derived dissolved organic matter from invasive plant and binding behavior with the selected pharmaceuticals

A comprehensive understanding of the characteristics of biochar released-dissolved organic matter (BDOM) derived from an invasive plant and its impact on the binding behavior of pharmaceuticals is essential for the application of biochar, yet has received less attention. In this study, the binding behavior of BDOM pyrolyzed at 300-700 °C with sulfathiazole, acetaminophen, chloramphenicol (CAP), and carbamazepine (CMZ) was investigated based on a multi-analytical approach. Generally, the pyrolysis temperature exhibited a more significant impact on the spectral properties of BDOM and pharmaceutical binding behavior than those of the molecular weight. With increased pyrolysis temperature, the dissolved organic carbon decreased while the proportion of the protein-like substance increased. The highest binding capacity towards the drugs was observed for the BDOM pyrolyzed at 500 °C with the molecular weight larger than 0.3 kDa. Moreover, the protein-like substance exhibited higher susceptive and released preferentially during the dialysis process and also showed more sensitivity and bound precedingly with the pharmaceuticals. The active binding points were the aliphatic C-OH, amide II N-H, carboxyl CO, and phenolic-OH on the tryptophan-like substance. Furthermore, the binding affinity of the BDOM pyrolyzed at 500 °C was relatively high with the stability constant (logKM) of 4.51 ± 0.52.

Effect of different production methods on physicochemical properties and adsorption capacities of biochar from sewage sludge and kitchen waste: Mechanism and correlation analysis

Different pyrolysis methods, parameters and feedstocks result in biochars with different properties, structures and removal capacities for heavy metals. However, the role of each property on adsorption capacity and corresponding causal relationships remain unclear. Here, we investigated various physicochemical properties of biochar produced via three different methods and two different feedstocks to clarify influences of biomass sources and pyrolysis processes on biochar properties and its heavy metal adsorption performance. Experimental results showed biochars were more aromatic and contained more functional groups after hydrothermal carbonization, while they had developed pores and higher surface areas produced by anaerobic pyrolysis. The inclusion of oxygen resulted in more complete carbonization and higher CEC biochar. Different biochar properties resulted in different adsorption capacities. Biochar produced by aerobic calcination showed higher adsorption efficiency for Cu and Pb. Correlation analysis proved that pH, cation exchange capacity and degree of carbonization positively affected adsorption, while organic matter content and aromaticity were unfavorable for adsorption. Microstructure and components determined biochar macroscopic properties and ultimate adsorption efficiency for metal ions. This study identifies the degree of correlation and pathways of each property on adsorption, which provides guidance for targeted modification of biochar to enhance its performance in heavy metal removal.

Pretreatment of marine sediment for the removal of di-(2-ethylhexyl) phthalate by sulfite in the presence of sorghum distillery residue-derived biochar and its effect on microbiota response

This study investigates the mechanism behind the oxidation di-(2-ethylhexyl) phthalate (DEHP) in marine sediment by coupling sulfite using biochar prepared from sorghum distillery residue (SDRBC). The rationale for this investigation stems from the need to seek effective methods for DEHP-laden marine sediment remediation. The aim is to assess the feasibility of sulfite-based advanced oxidation processes for treating hazardous materials such as DEHP containing sediment. To this end, the sediment in question was treated with 2.5 × 10-5 M of sulfite and 1.7 g L-1 of SDRBC700 at acidic pH. Additionally, the study demonstrated that the combination of SDRBC/sulfite with a bacterial system enhances DEHP removal. Thermostilla bacteria were enriched, highlighting their role in sediment treatment. This study concludes that sulfite-associated sulfate radicals-driven carbon advanced oxidation process (SR-CAOP) offers sustainable sediment pretreatment through the SDRBC/sulfite-mediated microbial consortium, in which the SO3•- and 1O2 were responsible for DEHP degradation. SDRBC/sulfite offers an effective and environmentally friendly method for removing DEHP. Further, these results can be targeted at addressing industry problems related to sediment treatment.