Effects of dairy manure biochar on adsorption of sulfate onto light sierozem and its mechanisms

Abstract

The adsorption of nitrogen and phosphorous nutrients on biochar and even biochar-soil mixtures was investigated. However, the situation of sulfur was not very clear. Here, sulfate (SO 4 2À ) adsorption onto dairy manure biochar obtained at 700 C (DMBC700), soil (light sierozem) and a 1 : 9 (w/w) biochar-soil mixture (DMBC700-soil) was investigated using batch experiments. The contact time, sulfate concentration, and solution pH value were chosen as the main factors; their effects on sulfate adsorption were tested, and the kinetics and isotherms were also investigated. Fourier transform infrared (FTIR) and X-ray diffraction (XRD) spectroscopies were used to characterize DMBC700 and soil before and after adsorbing sulfate, respectively, and to analyze the mechanisms of adsorption. The results showed that the adsorption kinetics were well described by the pseudo-second-order model, whereas the Langmuir and Freundlich models fitted well with the equilibrium data. DMBC700 modification did not increase the adsorption capacity of light sierozem for sulfate. When the pH values of the initial solution were increased, all the adsorption capacities of sulfate onto DMBC700, light sierozem and light sierozem with DMBC700 decreased. The electrostatic interaction was the main force for the adsorption of sulfate onto DMBC700, whereas both electrostatic interaction and formation of poorly soluble CaSO 4 were the main forces for adsorption of sulfate onto light sierozem. DMBC700 was found to have negative effect on sulfate adsorption onto light sierozem.

Highly Porous and Nutrients-Rich Biochar Derived from Dairy Cattle Manure and Its Potential for Removal of Cationic Compound from Water

“…For instance, the BET surface area of DM-BC (ca. 300 m 2 /g) was significantly higher than those (<186.5 m 2 /g) by other similar studies using dairy manure for the preparation of biochars [6][7][8][9][10][11][12][13][14]. Based on the microporosity (i.e., the ratio of micropore surface area to BET surface area), listed in Table 1, it was close to 0.70, giving an indication of a mesoporosity of about 30%.…”

“…Although there are many researches reusing dairy cattle manure as a feedstock for biochar production, only few studies focused on using the dairy manure-based biochar as an adsorbent or biosorbent for the removal of pollutants from the aqueous solution and soil systems [6][7][8][9][10][11][12][13][14]. Cao and other researchers [6,7] prepared the biochars at low temperatures (200-500 • C), indicating that the resulting biochar (SSA 2.7-13 m 2 /g) can be used as an effective sorbent for removal of lead and atrazine from the aqueous solution.…”

“…Chen et al [13] reported the removal of Cd and Pb with the biochars (including the biochar modified by NaOH treatment; SSA 9.4 and 25.9 m 2 /g) produced at 300 • C, revealing that the sorption mechanisms are predominantly controlled by chemisorption and complexation with carboxyl/hydroxyl functional groups. Zhao et al [14] prepared the biochar (SSA 74 m 2 /g) obtained at 700 • C for studying its effects on adsorption of sulfate, showing that the electrostatic interaction between the biochar and sulfate ion could be the determining adsorption mechanism.…”

Characterization of Biochars Produced from Dairy Manure at High Pyrolysis Temperatures

“…In order to increase the biochar CEC by embedding more acidic oxygen functional groups on the surface, biochar was further treated with strong oxidants like hydrogen peroxide [39] and ozone [40]. Therefore, the removal of cationic pollutants (e.g., heavy metal ions, cationic dye) from aqueous solutions by using DM-based biochars has been widely studied in the literature [10][11][12][13][14][15][16][17]. Figure 6 showed the elemental compositions on the surfaces of the optimal product DMC-900 by the energy dispersive X-ray spectroscopy (EDS).…”

Co-application of high temperature biochar with 3,4-dimethylpyrazole-phosphate treated ammonium sulphate improves nitrogen use efficiency in maize

“…Biochar could also decrease the availability of S due to the sorption of SO 4 2− by electrostatic interaction with the charged surface of biochar 44 . The decline in the content of sulphate by biochar application has been reported due to the formation of weakly soluble CaSO 4 45 .…”