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The use of advanced treatment technologies such as pyrolysis and carbonization of bio-waste materials has the promise to develop coupled solutions for organic C and P problems in the future of food processing. Sewage sludge-derived pyrogenic materials that are applied to the soil system contain notable levels of P (1–20%). However, only a small portion of total phosphorus is available for plants. Therefore, our study assessed the pretreatment of sewage sludge with Na2CO3 and subsequent pyrolysis at 400 °C and 500 °C for the production of MPCM400 and MPCM500 as potential alternatives for inorganic P fertilizers. Non-pretreated sewage sludge-derived pyrogenic carbonaceous materials (PCM400 and PCM500) were produced as controls. The derived materials obtained by slow pyrolysis at a residence time of 120 min and pyrolysis temperatures of 400 °C and 500 °C, were analyzed by determination of electrical conductivity (EC), pH, elemental analysis of total C, H, N, scanning electron microscopy (SEM) and total concentrations of P, Cd, Fe, Pb and Zn. PCM400, PCM500, MPCM400 and MPCM500 were characterized by analysis of total 16 US-EPA (U.S. Environmental Protection Agency) PAHs by a toluene extraction procedure. Additionally, PCM400, PCM500, MPCM400 and MPCM500 were tested by a germination test with cress seeds (Lepidium sativum L.) and a short-term rye seedling test. Total C concentrations were raised in the order: MPCM500 < MPCM400 < PCM500 < PCM500. Concentration of Σ16 US-EPA PAHs was almost five times higher at PCM500 (21.87 mg/kg) compared to PCM400 (4.38 mg/kg) and three times higher at MPCM500 (23.12 mg/kg) compared to MPCM400 (7.55 mg/kg) with a dominant role of two and three-ring aromatic structures. Total P-concentrations in rye biomass increased in the order for the controls: (2.43 ± 0.95 mg/g) < PCM400 (3.57 ± 0.27 mg/g) < PCM500 (4.04 ± 0.24 mg/g) < MPCM400 (5.23 ± 0.09 mg/g) < MPCM500 (5.57 ± 0.70 mg/g) < IF (7.53 ± 2.65 mg/g). Obtained results showed that pyrolysis materials produced from sewage sludge represent a potential alternative of conventional P inorganic fertilizers and organic C suppliers. [ABSTRACT FROM AUTHOR]

Although the suitability of some biochars for contaminants' sorption separation has been established, not all potential feedstocks have been explored and characterized. Here, we physicochemically characterized cherry pit biochar (CPB) pyrolyzed from cherry pit biomass (CP) at 500 °C, and we assessed their As and Hg sorption efficiencies in aqueous solutions in comparison to activated carbon (AC). The basic physicochemical and material characterization of the studied adsorbents was carried out using pH, electrical conductivity (EC), cation exchange capacity (CEC), concentration of surface functional groups (Boehm titration), and surface area (SA) analysis; elemental C, H, N analysis; and Fourier-transform infrared spectroscopy (FTIR) and scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM–EDX). AsO43− anions and Hg2+ cations were selected as model contaminants used to test the sorption properties of the sorption materials. Characterization analyses confirmed a ninefold increase in SA in the case of CPB. The total C concentration increased by 26%, while decreases in the total H and N concentrations were observed. The values of carbonate and ash contents decreased by about half due to pyrolysis processes. The concentrations of surface functional groups of the analyzed biochar obtained by Boehm titration confirmed a decrease in carboxyl and lactone groups, while an increase in phenolic functional groups was observed. Changes in the morphology and surface functionality of the pyrolyzed material were confirmed by SEM–EDX and FTIR analyses. In sorption experiments, we found that the CPB showed better results in the sorption separation of Hg2+ than in the sorption separation of AsO43−. The sorption efficiency for the model cation increased in the order CP < CPB < AC and, for the model anion, it increased in the order CPB < CP < AC. [ABSTRACT FROM AUTHOR]