Abstract
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.
Highlights
Ceaseless industrialization and population growth across the world have led to a severe deterioration in water quality [1].e use of chemicals and industrial compounds has continued to increase, posing a significant pollution risk to existing watercourses
Characterizations of the Material. e crystal structure of the obtained activated carbon (AC)/Fe3O4 composite was determined using the X-ray diffraction (XRD) technique. e XRD pattern of the composite (Figure 2) was analyzed using JCPDS, with all the peaks matching the reported magnetite pattern (PDF no. 01-0716336). e pattern appeared in the form of broad bands, possibly due to the low iron content and/or the small crystalline size of the magnetite formation dispersed over the carbon matrix. e existence of magnetite in the composite was confirmed by the vibration peak of Fe-O at about 584 cm−1 [30] in the Fouriertransform infrared spectroscopy (FTIR) spectrum (Figure 3). e characteristic vibration peaks corresponding to AC were clearly observable, including the hydroxyl–OH group (3,635 cm−1), carbonyl C O (1,722 cm−1), C C (1,573 cm−1), and C-O (1,260 cm−1)
Conclusions e magnetic AC derived from macadamia nutshell residue was successfully prepared and utilized for the removal of zinc (II) ion in an aqueous solution
Summary
E use of chemicals and industrial compounds has continued to increase, posing a significant pollution risk to existing watercourses. Water pollution is a global environmental challenge that destroys the food sources and contaminates drinking water, leading to immediate and long-term effects on human health [2]. Many water pollutants are reported to act as toxic chemicals, including dyes, antibiotics, heavy metals, fertilizers, and pesticides [1, 2]. Heavy metal pollution is a major water pollution hazard and presents a serious risk to human health and aquatic environments [3, 4]. Zinc is among the metals that have a widespread use in galvanization, electroplating, and the manufacture of alloys, allowing it to accumulate in the environment [6]. Zinc is among the metals that have a widespread use in galvanization, electroplating, and the manufacture of alloys, allowing it to accumulate in the environment [6]. is element is essential for living organisms as playing a central role in the immune system and taking part of many metal-enzymes and metal-proteins; its excess in water can cause eminent health problems, such as stomach cramps, skin irritations, vomiting, nausea, and anemia [6, 7]. erefore, for many nations, the search for effective heavy metal treatments, especially for zinc ion, is a priority among their environmental and sustainable development strategies.
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