Removal of Cd (II) from water using the waste of jatropha fruit (Jatropha curcas L.)

Abstract

The aim of this work was to evaluate the removal of Cd (II) from water using three biosorbents originated from the biomass of jatropha (bark, endosperm, and endosperm ? tegument). For that, batch tests were performed to verify the effect of solution pH, adsorbent mass, contact time, initial concentration of Cd (II), and the temperature of the process. The adsorption process was evaluated by the studies of kinetics, isotherms, and thermodynamics. The ideal conditions of solution pH were 5.5 and 8 g L-1 of adsorbent mass of biosorbents by solution volume, with an equilibrium time of 60 min. According to the Langmuir model, the maximum adsorption capacity for bark, endosperm, and bark ? endosperm of jatropha was, respectively, 29.665, 19.562, and 34.674 mg g-1 , predominating chemisorption in monolayers. The biosorbents presented potential for the remediation of waters contaminated with Cd (II).

Some Properties of Electron Beam-Irradiated Sheep Wool Linked to Cr(III) Sorption

“…The varied representation of amino acids with different side chain type in keratin does not allow the determination of the IEP of sheep wool by direct calculation from pK a data. Therefore, the IEP was estimated at 0.05 M KCl, similar to other biosorbents of plant origin [28], where the effect of all components is involved. In addition, we tried to find the effect of wool irradiation on the PZC and IEP position, which is identified by the electrokinetic potential ξ [29].…”

“…While for simple amino acids IEP can be estimated by calculation from pK a data, for proteins, the IEP is understood to be the point at which the hydrogen ion concentration of a solution in which the ionization of the acid groups of the amphoteric substances, ampholytes, is equal to the ionization of the basic groups [30]. Here, the IEP estimation can be performed by measuring the change in pH of the wool extract in a neutral salt solution with set initial pH value following [28].…”

Adsorption of Cd (II), Pb (II) and Cr (III) on chemically modified Euterpe Oleracea biomass for the remediation of water pollution

“…In addition, authors such as Schwantes et al (2018a) brought up changes observed in the chemical composition after chemical modifications with H 2 SO 4 , NaOH and H 2 O 2 , in different vegetable biomass. Moreover, washing the material to neutral pH after the whole process may have contributed to the variation in the chemical composition of the adsorbents (Nacke et al, 2017;Schwantes, Gonçalves, Varennes, & Braccini, 2018b).…”

“…the process reaches the equilibrium. After that, the active sites of the adsorbent are depleted, and Q ads of Cd 2+ , Pb 2+ and Cr 3+ started to be controlled by the transport rate from the outside to the inside of the active sites of the particles of adsorbents (Nacke et al, 2017). This also mean that periods of contact time longer than 40 min.…”

Characterisation and Kinetic Studies on Activated Carbon Derived from Rubber Seed Shell for the Removal of Methylene Blue in Aqueous Solutions

“…The minimum period required to achieve equilibrium within the adsorption system can be obtained through an analysis of contact time between the adsorbent and MB dye. 25 The relationship between contact time and the percentage removal of MB dye by RSSAC is shown in Figure 8. Based on Figure 8, the highest percentage removal of MB dye was observed at 1 h for RSSAC with a percentage removal of 99.62%.…”