Fruit Peels as Efficient Renewable Adsorbents for Removal of Dissolved Heavy Metals and Dyes from Water

Abstract

Removal of heavy metal ions and dissolved organic compounds present in wastewater is a challenge for many countries owing to high cost of existing technologies and continued increase in water consumption. In this study, three natural materials, avocado, hamimelon and dragon fruit peels, were selected and used as simple and renewable adsorbents for water purification. The presence of surface functional groups such as −CO2H, −OH and morphologies of the peels were characterized using spectroscopic and electron microscopic techniques, respectively. All peals were effective toward removing dyes and toxic metal ions from water. The extraction capacity of peels increased with extraction time and a plateau was reached at equilibrium. Dragon fruit peels showed highest extraction efficiency toward alcian blue (71.85 mg/g) and methylene blue (62.58 mg/g). Hamimelon peels and avaocado peels showed moderate extraction capacity for Pb2+ (7.89 mg/g, 9.82 mg/g) and Ni2+ (9.45 mg/g, 4.93 mg/g) cations. The Langmuir isotherm model was useful to explain the adsorption process, dominated by electrostatic interaction between adsorbent and adsorbates, indicating a monolayer adsorption at the binding sites on the surface of the peels. However, the adsorption model for methylene blue and neutral red is still a matter of conjecture. The adsorbents can be regenerated at acidic pH and could reuse for a few cycles.

Core-Shell MnO2-SiO2 Nanorods for Catalyzing the Removal of Dyes from Water

“…It is estimated that 15% of the dye is lost during processes and is released in wastewater [2]. Dye pollutants are an important source of environmental contamination and cause significant pollution to groundwater [3]. Dyes are generally resistant to light and moderate oxidative agents.…”

“…A number of physical and physicochemical technologies have been developed for the removal of dyes from aqueous solutions, including adsorption techniques [3,4], membrane processes [5,6], and degradation of dyes through oxidation under the assistant of catalysts [7][8][9][10]. Various materials have been used as adsorbents for the removal of dyes, such as biocoagulants [1], fruit peels [3], and cellulose-based bioadsorbents [4].…”

“…Various materials have been used as adsorbents for the removal of dyes, such as biocoagulants [1], fruit peels [3], and cellulose-based bioadsorbents [4]. Mesoporous silica materials with a low toxicity have high specific areas and large interior spaces.…”

Surface‐Functionalized Electrospun Titania Nanofibers for the Scavenging and Recycling of Precious Metal Ions

“…This work offers av iable strategy not only for the removal of precious metal ions but also for recovering and furtherr ecycling them for use as catalysts. [5] More simple and effective methods for scavenging precious metal ions are still highly needed.Electrospinning is as imple, versatile, and powerful technique for producing large quantities of nanofibers and thus membranes in the form of nonwoven mats with high porosities and large specific surfacea reas. [1] In the final products, the concentration of preciousm etal ions leaching from the catalysts can often reach al evel of parts per million( ppm).…”

“…[2,3] Removalo fc atalytic materials from intermediate products is also an essential step to avoid possible complications in downstream processes. [5] More simple and effective methods for scavenging precious metal ions are still highly needed. Thus, removing metal ions from wastewater is am ajor problem faced by many countries.…”