Biochar amendments could enhance retention of nutrients such as ammonium (NH4+), nitrate (NO3-), and phosphate (PO43-) in soils. However, the situation for sulphate (SO42-), which is an indispensable nutrient element for crop growth, is unclear. In this paper, the effects of biochar derived from rape (Brassica campesstris L.) straw at 600°C on the sorption and leaching of SO42- in light sierozem (Calcids) was studied in columns, where biochar amendment rate, column soil height, solution pH value and initial sulphate concentration were selected as factors. It is shown that the transport of sulphate was a significant non-equilibrium process and the sorption and leaching curves (SLCs) of sulphate were asymmetrical. The breakthrough time would be increased by increasing biochar amendment and soil column height, and by decreasing solution pH value and initial sulphate concentration. The SLCs of bromide trace were fitted to determine dispersion coefficient (D) using equilibrium convection dispersion equation (CDEeq). The non-equilibrium (two-site) model (CDEnon-eq) with the results from CDEeq was used to simulate the transport processes of sulphate in the soil column, with good fitness, using software CXTFIT 2.1 fitting. The results could supply an implication for biochar application in loess areas.

The sorption capacities of the macrofungus viz. Ganoderma lobatum (C0) and its biochar (C400) were evaluated for the biosorption of Cu(II) from aqueous solution under different conditions, including adsorbent doses, pH of the solution, contact time and initial Cu(II) concentration. The results showed that Ganoderma lobatum could be used as an efficient biosorbent for the removal of Cu(II) ions from an aqueous solution. The desired biosorbent dose in the case of C0 and C400 for Cu(II) adsorption was 4 g/L, and the optimal pH value for biosorption was 8 for Cu(II). The Freundlich isotherm model fitted the absorption data of Cu(II) for both C0 and C400 better than the Langmuir isotherm model, and the adsorption capacity of C0 was better than C400. Our results indicate that C0 has a higher removal efficiency than C400 in adsorbing Cu(II) ions from aqueous solution. Biosorption kinetics were also studied using pseudo-first-order and pseudo-second-order models, which showed that the biosorption processes of Cu(II) ions based on C0 and C400 were in accordance with the pseudo-second-order kinetics.