Removal of Cd, Cr, and Pb from aqueous solution by unmodified and modified agricultural wastes

Abstract

The adsorption of cadmium (Cd), chromium (Cr), and lead (Pb), widely detected in wastewater, by unmodified and modified banana stalks, corn cob, and sunflower achene was explored. The three agricultural wastes were chemically modified with sodium hydroxide (NaOH), in combination with nitric acid (HNO3) and sulfuric acid (H2SO4), in order to improve their adsorptive binding capacity. The experiments were conducted as a function of contact time and initial metal ion concentrations. Of the three waste materials, corn cob had the highest adsorptive capacity for Pb than Cr and Cd. The NaOH-modified substrates had higher adsorptive capacity than the acid modified samples. The chemical treatment invariably increased the adsorption capacity between 10 and 100 %. The Langmuir maximum sorption capacity (q m) of Pb was highest (21-60 mg g(-1) of banana, 30-57 mg g(-1) of corn cob, and 23-28 mg g(-1) of sunflower achene) and that of Cd was least (4-7 mg g(-1) of banana, 14-20 mg g(-1) of corn cob, and 11-16 mg g(-1) of sunflower achene). The q m was in the order of Pb > Cr > Cd for all the three adsorbents. The results demonstrate that the agricultural waste materials used in this study could be used to remediate water polluted with heavy metals.

Insight into the adsorption mechanisms of methylene blue and chromium(iii) from aqueous solution onto pomelo fruit peel

“…The reason is that biosorbent has many signicant advantages such as simple implementation, very low cost, no or minimal use of chemicals and high efficiency, as compared to other materials. Several biosorbents have been used to treat MB and Cr(III) in waste solution such as oak banana peels, 11 sawdust, 27 lawn grass, 28 de-oiled algae, 29 mango leaves, 30 corn cobs, sunower 31 and grapefruit. 32 Pomelo, or Citrus maxima, has been popularly planted in Dong Nai Province, Vietnam.…”

Gemini Surfactant-Modified Activated Carbon for Remediation of Hexavalent Chromium from Water

“…Their maximum arsenic adsorption capacity varied from 370 ug/g to 1250 ug/g [25] 2. Materials and Methods…”

Adsorption of Cr(VI) by material synthesized from red mud and rice husk ash

“…It is commonly found in waste water from a variety of industries, such as tanning, electroplating, textile dyeing, etc. Cr(VI), even in low concentrations in waste water, can cause damage to the kidneys, lungs, liver, as well as stomach [1,2]. As a result of research, various techniques have been applied to remove Cr(VI) from waste water, including membrane filtration, ion exchange, electrolysis, adsorption, and biological techniques [3][4][5].…”