Macadamia Nutshell Biochar for Nitrate Removal: Effect of Biochar Preparation and Process Parameters

Abstract

Agricultural runoff is a major cause of degradation to freshwater sources. Nitrate is of particular interest, due to the abundant use of nitrogen-based fertilizers in agricultural practices globally. This study investigated the nitrate removal of biochar produced from an agricultural waste product, macadamia nutshell (MBC). Kinetic experiments and structural analyses showed that MBC pyrolsed at 900 • C exhibited inferior NO 3 − removal compared to that pyrolsed at 1000 • C, which was subsequently used in the column experiments. Concentrations of 5, 10 and 15 mg/L, with flowrates of 2, 5 and 10 mL/min, were examined over a 360 min treatment time. Detailed statistical analyses were applied using 2 3 factorial design. Nitrate removal was significantly affected by flowrate, concentration and their interactions. The highest nitrate removal capacity of 0.11 mg/g MBC was achieved at a NO 3 − concentration of 15 mg/L and flowrate of 2 mL/min. The more crystalline structure and rough texture of MBC prepared at 1000 • C resulted in higher NO 3 − removal compared to MBC prepared at 900 • C.The operating parameters with the highest NO 3 − removal were used to study the removal capacity of the column. Breakthrough and exhaustion times of the column were 25 and 330 min respectively. Approximately 92% of the column bed was saturated after exhaustion.

Synthesis and characterization of micro-nano carbon filler from Jatropha seeds

“…In a similar study on adsorption capabilities, Bakly et al (2019) reported nitrate removal with macadamia nutshell biochar from slow pyrolysis; more than 45% of nitrate was removed at the highest concentration and at the lowest flow rate. Bakly et al (2019) also attributed the adsorption capabilities to the biochar size, porosity, and surface area; the biochar samples were ground and sieved with a size range of 1.18 mm to 2.30 mm before adsorption testing. Furthermore, agricultural runoff is a major cause of degradation to freshwater sources, so the removal of nitrate content is a concern, due to the abundance of nitrogen-based fertilizers in agriculture (Bakly et al 2019).…”

“…Li et al (2019) reported microwave-pyrolysis biochar of Artemisia selengensis and its adsorption capacity for methylene blue, for which biochar pores, surface area, and pyrolysis conditions influenced the adsorption capabilities (Li et al 2019). In a similar study on adsorption capabilities, Bakly et al (2019) reported nitrate removal with macadamia nutshell biochar from slow pyrolysis; more than 45% of nitrate was removed at the highest concentration and at the lowest flow rate. Bakly et al (2019) also attributed the adsorption capabilities to the biochar size, porosity, and surface area; the biochar samples were ground and sieved with a size range of 1.18 mm to 2.30 mm before adsorption testing.…”

“…Bakly et al (2019) also attributed the adsorption capabilities to the biochar size, porosity, and surface area; the biochar samples were ground and sieved with a size range of 1.18 mm to 2.30 mm before adsorption testing. Furthermore, agricultural runoff is a major cause of degradation to freshwater sources, so the removal of nitrate content is a concern, due to the abundance of nitrogen-based fertilizers in agriculture (Bakly et al 2019).…”

Biochar Effects on Nutrients Retention and Release of Hydroponics Growth Media

“…Beck et al (2011) also showed that adding biochar to green roof trays increased nitrate retention. The retention of nitrate onto biochar could be attributed to the electrochemical interaction and binding with the functional groups (Bakly et al, 2019). Steam activation of biochar almost doubled the positive effects of biochars for nutrient retention, and this highlights the need for further investigation for effective application of biochar in hydroponic systems (Borchard et al, 2012).…”

Metabolite Profiling and Transcriptome Analyses Provide Insight Into Phenolic and Flavonoid Biosynthesis in the Nutshell of Macadamia Ternifolia

“…In addition, Macadamia nutshell is used to produce biomass pyrolysis through controlled high-temperature serial reactions ( Poinern et al, 2011 ). Several pyrolysis-based biochar applications include steel production ( Kumar et al, 2017 ), soil amendments ( Wrobel-Tobiszewska et al, 2018 ), and de-nitrification mechanism ( Bakly et al, 2019 ). Similarly, the nutshells of almond, hazelnut, walnut, and apricot are a cost-effective source of activated carbons for treatment of industrial effluents ( Aygün et al, 2003 ).…”