Dewaterability enhancement and heavy metals immobilization by pig manure biochar addition during hydrothermal treatment of sewage sludge

Treatment of high-ash industrial sludge for producing improved char with low heavy metal toxicity

“…The extraction of the total HMs was referred to the F4 procedure (Fig. S1b) [26]. The leaching toxicity of HMs was analyzed by taking the solution (sample to acetic acid ratio of 1:20) and shaking it for 18 h at 200 r/min, adhering to the toxicity characteristic leaching procedure (TCLP) [16].…”

“…The F1 and F2 fractions can be adsorbed on the particle surface or combined with carbonates and Fe-Mn hydroxides, demonstrating high biotoxicity in the environment and therefore, they are recognized as bioavailable fractions. The F3 fraction is bound with sulfides or organic matter, and the F4 is occluded in crystalline structures, which is considered a stable fraction [26], and thus, the stability of HM speciation is ranked as follows: F4 > F3 > F2 > F1. Fig.…”

Moderate sewage sludge biochar application on alkaline soil for corn growth: a field study

“…The samples (0.5 g) were extracted in turn using 20 mL of acetic acid (0.11 mol/L), 20 mL of hydroxylamine hydrochloride (0.5 mol/L), 10 mL of hydrogen peroxide (30%) digestion, and 25 mL of ammonium acetate (1 mol/L). Detailed information has been reported in the previous study (Xie et al 2019(Xie et al , 2020b. Specifically, F1 is the fraction from acid-soluble or carbonate-combined metals, F2 is the fraction combined with iron and manganese oxides, F3 is the fraction associated with sulfur or organic matter, and F4 is the fraction bound to silicate minerals.…”

Preparation of biochar via pyrolysis at laboratory and pilot scales to remove antibiotics and immobilize heavy metals in livestock feces

“…Leaching experiments: The availability and toxicity heavy metals in PM, CM and the biochar samples were impacted by their leachability assessed by the toxicity characteristic leaching procedure (TCLP) (Xie et al 2019). For the TCLP, the glacial acetic acid solution with pH of 2.88 was used for extraction with liquid/solid ratio of 20:1.…”

“…(Khorram et al 2016;Zhang et al 2016). (Xie et al 2019). Some other researches were conducted to investigate the effect of pyrolysis on heavy metals immobilization during manures treatment.…”