Effects of a manganese oxide-modified biochar composite on adsorption of arsenic in red soil

Abstract

The arsenic adsorption capacity of a manganese oxide-modified biochar composite (MBC), prepared by pyrolysis of a mixture of potassium permanganate and biochar, was investigated in red soil. Adsorption experiments using batch procedures were used to estimate the arsenic adsorption capacities of the absorbent materials. Adsorption and desorption isotherms, Fourier-transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS) were used to characterise the prepared adsorbent materials, and a plausible mechanism for arsenic removal by MBC was proposed. Arsenic in red soil-MBC mixtures exhibited lower mobility than that in soils amended with pristine biochar. The improved removal performance of soil-MBC mixtures was attributed to a lower H/C ratio, higher O/C ratio, higher surface hydrophilicity, and higher surface sorption capacity, even though the impregnation of manganese oxide decreased the specific surface area of the biochar. Arsenic retention increased as the biochar content increased, mainly owing to an increase in soil pH. Several oxygenated functional groups, especially O-H, CO, Mn-O, and Si-O, participated in the adsorption process, and manganese oxides played a significant role in the oxidation of arsenic. This study highlights the potential of MBC as an absorbent to immobilise arsenic for use in contaminated land remediation in the red soils region.

Titanium dioxide‐coated biochar composites as adsorptive and photocatalytic degradation materials for the removal of aqueous organic pollutants

“…Recently, there have been various reports on the utilisation of BC for wastewater treatment and remediation of contaminated soil, owing to its cost‐effectiveness for the removal of chemical contaminants, namely, heavy metals and organic contaminants . There have also been several interesting proposals for the use of BC as a stabiliser of nano‐sized metal oxides which tend to aggregate because of their high surface energy and strong magnetic attraction, leading to reduced effective surface area and contact area when used for the removal of pollutants . For instance, Jung et al .…”

“…[3][4][5][6][7][8] There have also been several interesting proposals for the use of BC as a stabiliser of nano-sized metal oxides which tend to aggregate because of their high surface energy and strong magnetic attraction, leading to reduced effective surface area and contact area when used for the removal of pollutants. [9][10][11][12][13][14] For instance, Jung et al explored combined electrochemical modifications for the fabrication of a MgO/biochar composite which exhibited excellent aqueous phosphate adsorption properties represented by a Langmuir-Freundlich maximum adsorption capacity of 620 mg-P g -1 . 15 Zhang et al synthesised a magnetic BC material through thermal pyrolysis and demonstrated that the material is an excellent sorbent for the removal of arsenic (V) from an aqueous solution.…”

Arsine adsorption in copper-exchanged zeolite under low temperature and micro-oxygen conditions

“…5 illustrates that the As 2p peak is centered at 1328.2 eV, indicating the possible presence of As 2 O 5 . 28 The As species appearing in Cu/Hb-AsH 3 are likely to be formed via an oxidation process. Freshly prepared Cu/Hb adsorbent shows no signs of As species, whereas aer adsorption, it clearly contains As species.…”

Effect of preparation methods on morphology of active manganese dioxide and 2,4-dinitrophenol adsorption performance

“…Moreover, owing to the high oxidation potential ( E 0 = 1.23 V), manganese oxide could participate in a wide range of chemical oxidation reactions (Cheng et al., 2017; Guo et al, 2017). Manganese dioxide has been widely researched as adsorbents and catalysts for environmental remediation purposes, such as organic dye (Ge and Qu, 2003), phenolic compounds (Wang et al, 2015; Zhang et al, 2011), heavy metal (Peng et al, 2015; Yu et al, 2015), humic acid (Davranche et al, 2008), and endocrine disrupting compounds (Rudder et al, 2004).…”