Kinetic study on phosphate removal from aqueous solution by biochar derived from peanut shell as renewable adsorptive media

Abstract

As an alternative strategy for phosphate removal, biochar (black carbon) has characteristics superior to those of widely used adsorptive media, from both economic and environmental points of view. In this study, various types of biochar derived from oak wood, bamboo wood, maize residue, soybean stover, and peanut shell were tested for evaluation of phosphate removal. After 24 h of reaction time, the phosphate removal was limited (2.0-9.4 %) in case of general adsorptive media. However, interestingly, among various biochars, peanut shell-derived biochar (PSB) exhibited the best performance, showing the highest phosphate removal rate, 61.3 % (3.8 mg PO 4-P g PSB -1 ). We attribute this high value to the proper structural properties of PSB, such as BET-specific surface area of 348.96 m 2 g -1 and mineral/phosphorus ratio (Mg/ P = 3.46 and Ca/P = 47.6). Adsorption equilibrium and kinetics of phosphate at different temperature (10, 20, and 30°C) were well explained in the whole experimental region by Langmuir isotherm and pseudo-second-order kinetic models, respectively. The maximum adsorption capacity of PSB was 6.79 mg g -1 for phosphate at 30°C. These findings suggest that PSB has great potential as an alternative and renewable adsorptive media for phosphate removal.

Pyrolysis temperature and steam activation effects on sorption of phosphate on pine sawdust biochars in aqueous solutions

“…[43] The release of P may also occur due to low Ca content in biochar. [44,45] For biochars that do not contain abundant metal ions, it will be difficult for adsorption to occur when repulsive electrostatic forces exist. For example, Yao et al [44] tested thirteen biochars for P adsorption and found that most of them had little or no ability to adsorb P in a sandy soil.…”

“…For example, Yao et al [44] tested thirteen biochars for P adsorption and found that most of them had little or no ability to adsorb P in a sandy soil. Recently, Jung et al [45] found that among the five different biochars they tested only the biochar derived from peanut shell had good adsorptive capacity because of a proper Ca/P ratio. Apparently, biochar's adsorption capacity largely depends on feedstocks with different mineral compositions.…”

Characteristics of biochar derived from marine macroalgae and fabrication of granular biochar by entrapment in calcium-alginate beads for phosphate removal from aqueous solution

“…In addition, the phosphate concentration after mixing PB with only distilled deionized water was also increased up to 3.64 mg L À1 . According to previous reports, the phosphate holding capacity significantly depends on the divalent cation bridging and the ratios of Ca/P and Mg/P in the biochar (Hale et al, 2013;Jung et al, 2015a). As shown in Table 1, the Ca/P and Mg/P ratios of PB were lower than 1.0, which means that PB cannot hold the P content in biochar due to its low ionic strength, and thereby the P content should be released to the aqueous solution.…”

Co2+ ion adsorption behavior on plum stone carbon prepared by a solid-combustion process

“…(2016) [1][2][3][4][5][6][7][8][9][10][11][12] www.deswater.com doi: 10.1080/19443994.2016.1163512 agricultural waste have been used [8][9][10][11][12][13][14]. For instance, activated carbon has been widely recognized as the oldest and most versatile adsorbent used in wastewater treatment to remove diverse organic and inorganic pollutants due to its large specific surface area, high adsorption capacity, porous structure, and good selective adsorption characteristics, which depend on their precursors as well on the synthesis method [15].…”