Recovery of phosphate from aqueous solution by magnesium oxide decorated magnetic biochar and its potential as phosphate-based fertilizer substitute

Abstract

The present study deals with the preparation of a novel MgO-impregnated magnetic biochar (MMSB) for phosphate recovery from aqueous solution. The MMSB was evaluated against sugarcane harvest residue biochar (SB) and magnetic biochar without Mg (MSB). The results showed that increasing Mg content in MMSB greatly improved the phosphate adsorption compared to SB and MSB, with 20% Mg-impregnated MMSB (20MMSB) recovering more than 99.5% phosphate from aqueous solution. Phosphate adsorption capacity of 20MMSB was 121.25mgP/g at pH 4 and only 37.53% of recovered phosphate was desorbed by 0.01mol/L HCl solutions. XRD and FTIR analysis showed that phosphate sorption mechanisms involved predominately with surface electrostatic attraction and precipitation with impregnated MgO and surface inner-sphere complexation with Fe oxide. The 20MMSB exhibited both maximum phosphate sorption and strong magnetic separation ability. Overall, phosphate-loaded 20MMSB significantly enhanced plant growth and could be used as a potential substitute for phosphate-based fertilizer.

Removal of cadmium(II) cations from an aqueous solution with aminothiourea chitosan strengthened magnetic biochar

“…About 50 g of sycamore tree sawdust was immersed into the prepared FeCl 3 solution (1 L, 0.1 mol/L) for 24 h, and then, the separated solid mixture was oven‐dried overnight (80 °C). After that, both the FeCl 3 ‐treated and the pristine sawdust was pyrolyzed in a furnace at 550 °C in a N 2 atmosphere for 1 h, as reported before . The pyrolyzed products of the nontreated sawdust and treated sawdust were called BC and BC–Fe 3 O 4 (MBC), respectively.…”

“…Nevertheless, it is difficult for BC to be reused and separated after adsorption treatments because of its low density and fine dispersion of powder particles. Recently, some researchers developed engineered magnetic biochar (MBC) adsorbents to solve its deficiency . Although the adsorption capabilities of BC or synthesized MBC adsorbents were still very limited, improvements in these BC adsorbents' capacities were still needed to make them more practicable .…”

“…Recently, some researchers developed engineered magnetic biochar (MBC) adsorbents to solve its deficiency . Although the adsorption capabilities of BC or synthesized MBC adsorbents were still very limited, improvements in these BC adsorbents' capacities were still needed to make them more practicable . Similarly, as a low‐cost natural‐based material, chitosan (CS) may be an effective candidate for BC adsorbent modification …”

Chemical forms and risk assessment of heavy metals in sludge-biochar produced by microwave-induced low temperature pyrolysis

“…What is more, protein decomposition could give rise to an increase in C/N. 33,34 From the surface characteristics of biochar, it could be concluded that high temperatures had a positive inuence on improving the BET surface area. Compared with the heavy metal content in sludge, the contents in biochar became higher.…”

Effective treatment of high phosphorus pharmaceutical wastewater by chemical precipitation

“…However, the TP removal increased from 91.9 % to 96.3 % when the CaCl 2 /TP molar ratio was more than 1.6:1. The residual pH by MgCl 2 and CaCl 2 changed from 13 to 11.5 and 13 to 12 after the precipitation reaction, respectively, indicating MgCl 2 and CaCl 2 consumed less alkalinity than FeCl 3 in the precipitation reaction . Figure also shows that the TP removal rates obtained by FeCl 3 , AlCl 3 , MgCl 2 , and CaCl 2 were 84.2 %, 79.8 %, 78.6 %, and 96.3 % at the optimal Metal/TP molar ratio, respectively.…”