Macadamia Nut Shell Research Articles

Endocrine Disruptors-(estrone and β-estradiol) removal from water by Nutshell activated carbon: Kinetic, Isotherms and Thermodynamic studies

A large number of substances in the environment designated as endocrine-disrupting chemicals (EDCs) are amongst the most intoxicating compounds found in environmental waters. The removal of two EDCs: estrone (E1) and β-estradiol (E2) by activated carbon was examined in an agitated non-flow batch adsorption studies. The macadamia nutshell activated carbon (MAC) was characterized by TGA, FTIR, and SEM. Properties such as contact time, adsorbent dosage, pH, initial steroids concentration, and temperature were examined. Mathematical models like pseudo-first-order and pseudo-second-order kinetics, thermodynamic, the Freundlich, and Langmuir isotherms model were used to describe the steroids adsorption phenomenon. From the Langmuir isotherm, maximum adsorption capacity was found to be 22.0 mg/g. Thermodynamic factors: ∆G° values of –1.223 to –1.308 kJ/mol, ∆H° = –11.72 kJ/mol, and ∆S° = 37.34 J/mol k of steroids adsorbed onto MAC indicate that the adsorption was spontaneous, proceeded favourably at lower temperature and exothermic in nature, demonstrating that physisorption mechanism predominates. The distinctive data and adsorption intensity disclosed that MAC could be engaged as a substitute for effective adsorbents for the removal of endocrine disruptors-steroids from water.

Systematic study of dynamic CO2 adsorption on activated carbons derived from different biomass

In this work, biomass wastes (chestnut shells, walnut shells and macadamia nut shells) were used as raw materials, and a series of activated carbons (ACs) with high micropore percentage were prepared by hydrothermal carbonization and chemical activation methods, and their dynamic CO2 adsorption capacity was systematically studied. Then the effect of activation conditions and adsorption conditions were all investigated, and the hydrothermal conditions were evaluated in detail. In particular, the relationship between the CO2 uptake and textural properties such as micropore percentage and pore structure was discussed. The results show that the desired AC derived from walnut shells show superior CO2 uptake up to 2.24 mmol g−1 under the dynamic condition, which is comparable with the literature reported. It is also found that the micropore percentage has an important influence on the application of AC for CO2 capture. Both carbonization and activation conditions have significant impact on the CO2 uptake of AC. In addition, to control the CO2 inlet flow rate is essential to obtain a better adsorption effect. This work will give an effective guide to the fabrication of biomass derived AC, particular in preparation of AC based CO2 adsorbents.

Effect of Alkaline Treatment and Coupling Agent on Thermal and Mechanical Properties of Macadamia Nutshell Residues Based PP Composites

The influence of alkaline treatment on the thermal and mechanical properties of polypropylene (PP) reinforced with fibers from macadamia nutshell (5 to 30 wt%) was studied. To improve the interaction between fiber and matrix, the fibers were submitted to an alkaline treatment, as well as a coupling agent (MAPP) was used. The composites were obtained in a thermokinetic mixer, milled, and injected. Then, the degradation temperature and the loss of mass of the composites, pure PP, and fibers were evaluated. The mechanical properties of the composites were also evaluated. The results indicated that the degradation peak of composites occurred at higher temperatures, which indicated that composite exhibited higher thermal stability at higher temperatures. The addition of raw and treated macadamia fibers to the PP increased the stiffness of the composites, as well as the use of a coupling agent when compared to the neat PP. However, the incorporation of 30 wt% treated fiber to the PP showed an enhancement of 67.5% in the tensile modulus. The morphological analysis enabled to evaluate the efficiency of the coupling agent and the treated fibers adhered to matrix. The response surface methodology (RSM) technique showed that the higher fiber content added to the PP enhanced the stiffness, and consequently reduced the impact strength of the materials.

A Sustainable Perspective for Macadamia Nutshell Residues Revalorization by Green Composites Development

Macadamia is a nut widely used globally in food, personal hygiene products, and human health. After removing the nut, high amounts of the shell residual, which is an underutilized material with high economic interest. This work presents a sustainable alternative to revalorize the macadamia nutshell residues (MR) developing the green composites. Polypropylene (PP) composites were prepared using different MR content (5, 10, 15, 20, 25, and 30 wt%) as a filler. The samples were investigated by Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis, scanning electron microscopy (SEM), mechanical tests (tensile and flexure) before and after water absorption tests, and Life Cycle Assessment (LCA). FTIR results indicated that the MR acted only by physical impediments, without chemical interactions between the filler and matrix. Thermal analysis showed a significant increase (~ 20 °C) in PP thermal stability after MR addition, probably due to the filler high lignin content, and SEM photomicrographs indicate that high MR contents resulted in little cracks and voids in the interface. However, the defects did not influence the mechanical performance, and the green composites showed superior elastic modulus (2401 MPa) than the pristine PP (1516 MPa) and similar tensile strength (~ 30 MPa), confirmed by the statistical analysis and corroborating with the theoretical percolation network (25 wt%). The composites showed low water absorption (up to 0.3%), reflecting in downward variations in the wet samples' mechanical behavior. It evidences the possibility to use these samples for water applications. LCA indicated that higher MR contents promoted lower environmental impacts than the classical handling of this residue, and the results indicated that 30 wt% MR is the better environmental option. However, the PP/MR-25% showed reduced environmental impacts and associated with other properties improvements, considered the better sample. This work shows the MR revalorization as a sustainable approach to expand green composites applications.

Novel Phosphorous-Based Deep Eutectic Solvents for the Production of Recyclable Macadamia Nutshell–Polymer Biocomposites with Improved Mechanical and Fire Safety Performances

Deep eutectic solvents (DESs), a new class of ionic liquid analogue solvents, provide excellent opportunities to chemically solubilize and functionalize wood components. Here, we synthesized a nove...

Approach in Macadamia integrifolia residue based low‐density polyethylene composites on mechanical and thermal performance

AbstractMacadamia nutshell residues are generated in large quantities, around 70%–77% for each ton produced, and it is a waste material with high techno‐economic potential. This work purpose a sustainable alternative to valorize macadamia nutshell residues (MN) as reinforcing in low‐density polyethylene (LDPE) composites through melt mixing, using different fiber contents (0, 5, 10, and 20 wt%), and investigate the influence of fibers (residues) in composites by mechanical tests and thermal analysis. The fibers addition has significantly increased the composites' stiffness compared with neat LDPE, causing a reduction of toughness and resilience, leading to lower impact energy absorption. The LPDE/MN20% composite obtained the best tensile and flexural mechanical performance, resulting in a maximum modulus, which implies an increase of 36.9% and 77.6% compared with the neat LDPE. The addition of macadamia fibers on the composites acted as nucleation points of spherulites, which promoted an increase in the crystallization degree. Consequently, better performance of mechanical properties was observed in the green composites. Thus, the macadamia nutshell residues present a promising future as filler in LDPE for enhancing composites' thermal and mechanical properties.

Solid fuel production from macadamia nut shell: effect of hydrothermal carbonization conditions on fuel characteristics

Hydrothermal carbonization (HTC) was employed to convert macadamia nut shell (MCNS) into solid fuel. The effect of hydrothermal conditions was examined by varying the reaction temperature (170, 200, and 230 °C) and water/biomass ratio (2, 3, and 5). The properties of hydrochar were assessed in term of mass yield, energy recovery, higher heating value (HHV), and atomic H/C and O/C ratios. The results showed that HHV of hydrochar was significantly higher than raw MCNS, and progressively increased with increasing HTC temperature while mass yield showed opposite trend. The solid yield from HTC process varied between 58.38 and 78.43% of the initial dry MCNS with HHV around 22-27 MJ/kg. The energy recovery of hydrochars via HTC was in a range of 82.5-93.2%. Higher HTC temperature also increased the degree of coalification and thermal stability of hydrochar by removing volatile matters from the biomass. The removal of carboxyl and -OH groups reduces the O/C ratio leading to the higher energy densification of hydrochars. Hydrochar produced via HTC at 230 °C possessed the highest HHV of 27 MJ/kg, and had the O/C and H/C ratios close to sub-bituminous coal. The findings indicated that hydrothermal carbonization is a potential method to convert agricultural waste such as macadamia nut shell into solid fuel without pre-drying process.

Utilization of Macadamia Nutshell Residue for the Synthesis of Magnetic Activated Carbon toward Zinc (II) Ion Removal

In this study, macadamia nutshell residue, a prevalent leftover and green agricultural waste in Vietnam, was utilized to prepare a magnetic activated carbon adsorbent. The obtained material was characterized by its surface functionalities, elemental composition, crystalline structure, and magnetic properties. The characterization results revealed that the composite comprised Fe3O4 nanoparticles attached to the carbon matrix. The saturation magnetization (Ms) of the composite was found to be 38.2 emu g−1, indicating a convenient separation of the solid adsorbent from aqueous media using an external magnetic field. The feasibility of removing zinc (II) ion from an aqueous solution of the activated carbon/Fe3O4 (AC/Fe3O4) composite was examined. The adsorption kinetics were best explained by the Elovich model and the pseudo‐second‐order model. The adsorption capacity at equilibrium and the initial rate of Zn2+ adsorption determined by the pseudo‐second‐order model were 22.73 mg g−1 and 4.18 mg g−1 min−1, respectively. The implications of this study are that a low‐cost, green, and magnetically separable material prepared by a large‐scale available solid waste can be a promising adsorbent for the elimination of heavy metals.

Synthesis of activated carbon from macadamia nutshells activated by H2SO4 and K2CO3 for methylene blue removal in water

Macadamia nutshell is a new absorbent material for wastewater treatment. This work is a report on the synthesis of activated carbon as an absorbent materials prepared from macadamia nutshells using H2SO4 and K2CO3 as activating agents for methylene blue (MB) removal in water. The results show that MB adsorption capacity reaches its highest at 250.22 mg/g in preparation conditions H2SO4:coke 1:1 after 45 min calcination time when using a H2SO4 agent. The MB adsorption capacity of the absorbent using the K2CO3 agent reaches the highest at 261.52 mg/g in preparation conditions K2CO3:coke 1:1 and 60 min calcination time. Activated carbon prepared from macadamia nutshells activated by H2SO4 agents achieved the best MB removal efficiency of 67.29% in optimal conditions at a dose of 1 g/L with a treatment time of 60 min. The K2CO3agent achieved the best MB removal efficiency of 98.55% in optimal conditions at a dose of 0.5 g/L at a treatment time of 45 min. Macadamia nutshells are a potential new material to prepare the activated carbon in order to remove toxic organic compounds in wastewater.

Toxic Metal Adsorption from Aqueous Solution by Activated Biochars Produced from Macadamia Nutshell Waste

Abundantly available biomass wastes from agriculture can serve as effective environmental remediation materials. In this study, activated biochar was fabricated from macadamia nutshell (MCN) through carbonization and chemical modification. The resultant biochars were used as adsorbents to remove toxic metal ions such as Cu2+ and Zn2+ from aqueous solutions. The results showed that the activated MCN biochar has a high adsorption capacity for toxic metal ions. When MCN biochar was activated with K2CO3, the adsorption efficiencies for Cu2+ and Zn2+ were 84.02% and 53.42%, respectively. With H3PO4 activation, the Cu2+- and Zn2+-adsorption performances were 95.92% and 67.41%, respectively. H2O2-modified MCN biochar had reasonable Cu2+- and Zn2+-adsorption efficiencies of 79.33% and 64.52%, respectively. The effects of pH, adsorbent concentration and adsorption time on the removal performances of Cu2+ and Zn2+ in aqueous solution were evaluated. The results exhibited that the activated MCN biochar showed quick adsorption ability with an optimal pH of 4 and 4.5 for both Cu2+ and Zn2+, respectively.

A comparative study of acid-treated, base-treated, and Fenton-like reagent-treated biomass for Cr(VI) sequestration from aqueous solutions.

A wide variety of biomass materials have been used for the removal of toxic chromium(VI) by biosorption. The current study investigated the efficacy of Macadamia nutshells treated with sodium hydroxide, nitric acid, and the Fenton-like reagent in the removal of Cr(VI). The adsorbents were characterized by FTIR, SEM, TGA, and elemental analysis. Effects of functional parameters influencing the adsorption of Cr(VI), solution pH (pH 1-11), contact time (5-250min), concentration of adsorbent (1-10g/L), and adsorbate concentration (10-200mg/L) were investigated. The optimum conditions for biosorption were pH 1.4, adsorbent dose of 5g/L, and 160min of contact time. In all cases, the base-treated adsorbent displayed superior performance compared to others, with highest percent removal of 98%. The adsorbate-adsorbent interactions were better explained by the Freundlich isotherm and the pseudo-first-order rate model. The Macadamia-based adsorbents are potentially useful for Cr(VI) removal from aqueous solutions. PRACTITIONER POINTS: Three different chemical activators were investigated for the modification of Macadamia surface. The base-treated material exhibited the highest specific surface area of 12.1m2 /g. The Cr(VI) adsorption performance for the base-treated material dwarfed the other materials. Excellent Cr(VI) removal efficiency in the presence of competitors was achieved.

Palladium nanoparticles dispersed on functionalized macadamia nutshell biomass for formic acid-mediated removal of chromium(VI) from aqueous solution

Driven by the need for sustainably sourced catalysts and the use of reaction systems that generate environmentally benign by-products, the present study aimed to deposit stable, dispersed palladium (Pd) nanoparticles on the modified surfaces of granular macadamia nutshell (MNS) biomass for catalytic reduction of hexavalent chromium (Cr(VI)) to trivalent chromium (Cr(III)). Through wet impregnation with Pd(II) ions and subsequent hydrazine-mediated reduction to Pd(0), Pd nanoparticles were embedded in a scaffold of polyethyleneimine grafted on bleached MNS previously coated with a chemically bound layer of polyglycidyl methacrylate. Imagery from scanning electron microscopy showed the formation of different layers of the polymeric coating and dispersed palladium resulting from surface modification and palladium nanoparticle synthesis, respectively. X-ray diffraction analysis confirmed the formation of Pd on the modified MNS surface and suggested an estimated crystallite size of 5.0 nm. The supported nanoparticles exhibited catalytic activity in formic acid-mediated Cr(VI) reduction and showed promising stability with consecutive reuse. These findings set the stage for advanced studies into performance optimization.

The Equilibrium, Kinetics, and Thermodynamics Studies of the Sorption of Methylene Blue from Aqueous Solution Using Pulverized Raw Macadamia Nut Shells.

In this study, the potential for pulverized raw macadamia nut shell (MNS) for the sequestration of methylene blue from aqueous media was assessed. The sorbent was characterized using scanning electron microscopy for surface morphology, functional group analysis was performed with a Fourier-transform infrared spectrometer (FT-IR), and Brunauer–Emmett–Teller (BET) isotherm was used for surface area elucidation. The effects of contact time, sorbent dosage, particle size, pH, and change in a solution matrix were studied. Equilibrium data were fitted using Temkin, Langmuir, and Freundlich adsorption isotherm models. The sorption kinetics was studied using the Lagergren pseudo-first-order, pseudo-second-order, Elovich, and intraparticle diffusion models. The feasibility of the study was established from the thermodynamic studies. A surface area of 2.763 m2/g was obtained. The equilibrium and kinetics of sorption was best described by the Langmuir and the pseudo-second-order models, respectively. The sorption process was spontaneous (−ΔG0=28.72 − 31.77 kJ/mol) and endothermic in nature (ΔH0=17.45 kJ/mol). The positive value of ΔS0 (0.15 kJ/molK) implies increased randomness of the sorbate molecules at the surface of the sorbent. This study presents sustainable management of wastewater using MNS as a potential low-cost sorbent for dye decontamination from aqueous solution.

Microwave assisted modified macadamia nutshells/Cu-Mn oxide composite for the removal of Pb(II) from aqueous solution

The present study reports a novel composite material synthesized from acid modified macadamia nutshells (AMN) and Cu-Mn oxide under microwave heating for the removal of lead ions (Pb(II)) in water. The surface characterization of the material was carried out using powder XRD, FTIR, EDS, SEM, TGA, XPS, TEM, BET and zeta sizer. A series of batch adsorption experiments were carried out to investigate the adsorption behaviour of Pb(II) on AMN-Cu-Mn oxide. The adsorption kinetics and isotherms studies follow a pseudo second order model and Langmuir isotherm respectively with a maximum adsorption capacity of 34.5 mg/g at room temperature. The thermodynamic parameters indicate the endothermic and spontaneous nature of Pb(II) adsorption. The material adsorbed more than 95 % of Pb(II) in the presence of competing cations. AMN-Cu-Mn oxide was successfully recycled 4 times using 0.1 M HCl as leachate; 85 % Pb(II) was desorbed during the last adsorption-desorption cycle.

Fused Deposition Modeling of Poly (lactic acid)/Macadamia Composites-Thermal, Mechanical Properties and Scaffolds.

In this work Macadamia nutshell (MS) was used as filler in fused deposition modeling (FDM) of Poly (lactic acid) (PLA) composites filaments. Composites containing MS both treated and untreated with alkali and silane were investigated by means of Fourier transform infrared spectroscopy (FTIR), X-Ray diffraction (XRD), Thermogravimetry (TG), scanning electron microscopy (SEM). The results showed that the treated MS composites had better thermal stability. Furthermore, compression tests were carried out. The PLA with 10 wt% treated MS composite was found possessing the best mechanical properties which was almost equivalent to that of the pure PLA. Finally, porous scaffolds of PLA/10 wt% treated MS were fabricated. The scaffolds exhibited various porosities in range of 30–65%, interconnected holes in size of 0.3–0.5 mm, micro pores with dimension of 0.1–1 μm and 37.92–244.46 MPa of elastic modulus. Those values indicated that the FDM of PLA/MS composites have the potential to be used as weight lighter and structural parts.

A study of adsorption of Reactive Brilliant Red (K-2BP) by amino-modified macadamia nut shells

A study of adsorption of Reactive Brilliant Red (K-2BP) by amino-modified macadamia nut shells

CO2-cofeeding catalytic pyrolysis of macadamia nutshell

Here in this study, we laid great stress on a development of sustainable waste-to-energy (WtE) platform via CO2-cofeeding catalytic pyrolysis of macadamia nutshell (MNS) at mild temperature region. To this end, one-stage and two-stage (non-catalytic/catalytic) pyrolysis of MNS was performed to establish the fundamental relationship of temperature effect on syngas formation. The formation of gaseous pyrolysates was substantially enhanced when two-stage pyrolysis of MNS was applied, and second heating zone isothermally ran at 700 °C. Such the enhanced generation of gaseous pyrolysates from two-stage MNS pyrolysis of MNS was likely due to temperature-driven cracking of volatile organic compounds (VOCs). Also, catalytic two-stage pyrolysis of MNS was performed at lower isothermal running temperature (500 °C) over Ni/SiO2 and Co/SiO2. The enhanced formation of syngas (H2 and CO) was observed from catalytic pyrolysis of MNS. Therefore, pyrolysis of MNS over Ni/SiO2 or Co/SiO2 could be a reliable platform for enhancing syngas formation at mild temperature (≤ 500 °C) under CO2 environment. In addition, all experimental findings suggested that the use of CO2 is beneficial in the WtE platform, and the use of CO2 could be a practical climate change mitigation measure.

Agro Waste A Sustainable Source For Steel Reinforcement-Review

In this review paper the use of agro waste as a sustainable source for steel reinforcing steel was investigated. Agro waste is said to have certain amount of carbon which can be useful for steel reinforcement, as stated by different authors the carbon derived from agro waste is said to be of high quality. From literature it was observed that there is an increase in demand of agricultural produce which mean automatic increase in agricultural waste and this threat on humans, plants and the environment, this alone shows that agro waste is sustainable as it is currently been underutilized in the steel or iron making industry. In this review different agro waste such as macadamia nut shell, potato peel, husk from cereal, rice husk etc, and it was observed that macadamia nut shell has the highest carbon content which is about 92%. Agro waste is a sustainable source of obtaining carbon and should considered by steel producing companies as the carbon content is high and its environmentally friendly.

Studying the preparation of activated carbon from macadamia nut shells by chemical activation with NAOH in Methylene Blue treatment application

Study on preparation of activated carbons by chemical activation with NaOH using the impregnatio ratio of 3:1 (NaOH:char) from Macadamia nut shell in terms on temperature and time. The research result showed that Methylene Blue (MB) absorption at optimum temperature and time of 300oC and 90 minutes was 205,68 mg and the removal efficiency was 97,59% corresponding to the color reduction from 349,67 Pt-Co to 8,4 Pt-Co. This results showed that activated carbons prepared from Maccadia nut shells and chemical activation with NaOH had the capable of color treatment in textile wastewater.

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

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 NO3− 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 23 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 NO3− 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 NO3− removal compared to MBC prepared at 900 °C. The operating parameters with the highest NO3− 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.