Adsorption of Cu (II) and Ni (II) from aqueous solutions by taro stalks chemically modified with diethylenetriamine

Abstract

Taro stalks (TS) were modified by diethylenetriamine (DETA) to obtain the modified taro stalks adsorbents (recorded as MTSA). This kind of raw material is unprecedented and the method of modification is relatively simple. The physicochemical properties of MTSA were characterized by scanning electron microscope (SEM), FTIR, and zeta potential analyzer. The capacity of MTSA for adsorbing heavy metals under different influencing factors was tested by UV-visible spectrophotometer. The results indicated that the gaps between the microspheres of MTSA are more, which are conducive to adsorption. The MTSA might have increased the amino-functional groups which are beneficial for adsorption, resulting in an increase in the adsorption capacity of copper and nickel ions (35.71 and 31.06 mg/g) of about 5-7 times compared to bare taro stalks (5.27 mg/g and 6.08 mg/g). High Cu uptake on MTSA was observed over the pH range of 5.5-7.0, while for Ni the range was 7.0-8.5, and the optimum dosage of adsorbent were both about 0.80 g for Cu and Ni. The adsorption kinetics of Cu and Ni on MTSA could be interpreted with a pseudo-second order and the equilibrium data were best described by the Langmuir isotherm model. Graphical abstract ᅟ.

Hydrochars production, characterization and application for wastewater treatment: A review

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Adsorption of Hexavalent Chromium from an Aqueous Phase by Hydroxypropyl Methylcellulose Modified with Diethylenetriamine

“…It was observed that the infrared spectroscopy could be used to detect the surface functional groups of the adsorbent . Therefore, as Figure shows, the functional groups of HPMC, MHPMC, and MHPMC-loaded Cr (VI) were characterized by the Fourier infrared spectrometer (FT-IR).…”

“…The pH zpc value plays a very important role in adsorption materials, which determines the net electric neutral pH value on the surface of the adsorbent. , Generally, satisfying the pH < pH zpc inequality, the adsorbent surface is positively charged, which is favorable to the adsorption of the negatively charged chromium complex anions as a result of electrostatic attraction. On the contrary, at greater pH values (pH > pH zpc ), the surface of the adsorbent is negative, which leads to a decrease in the adsorption of chromium anions by the adsorbent as a result of electrostatic repulsion.…”

“…It was observed that the infrared spectroscopy could be used to detect the surface functional groups of the adsorbent. 27 Therefore, as Figure 5 shows, the functional groups of HPMC, MHPMC, and MHPMC-loaded Cr (VI) were characterized by the Fourier infrared spectrometer (FT-IR). The information conveyed from the diagram indicates that three infrared bands of MHPMC and HPMC both appear at 1643, 1452, and 1381 cm −1 , but the band of MHPMC is stronger than that of HPMC.…”

Modified Water Hyacinth Functionalized with Citric Acid as an Effective and Inexpensive Adsorbent for Heavy Metal-Ion Removal

“…This means that the overlap and aggregation of the adsorbent during the adsorption process reduce the number of adsorption sites. 22 Considering the changes of adsorption capacity and removal ratio, a lower adsorbent should be selected to prevent the adsorption capacity from being too small and save raw materials. Therefore, the optimal adsorbents for adsorption of Ni 2+ , Cu 2+ , and Cr 6+ were 0.65, 0.50, and 0.40 g, respectively.…”