Wheat Straws and Corn Straws as Adsorbents for the Removal of Cr(VI) and Cr(III) from Aqueous Solution: Kinetics, Isotherm, and Mechanism

Abstract

In this paper, the adsorption properties of wheat straw (WS) and corn straw (CS) for Cr(VI) and Cr(III) in solution were studied. The effects of adsorption time, pH of the solution, temperature, and initial concentration of metal ions on adsorption capacity were investigated. The adsorption mechanism was discussed. The results showed that the adsorption isotherms of WS and CS for Cr(VI) and Cr(III) satisfied the Langmuir equation. By fitting the Langmuir equation, the saturated adsorption capacity of WS for Cr(VI) and Cr(III) can reach 125.6 and 68.9 mg g −1 , and that of CS for Cr(VI) and Cr(III) can reach 87.4 and 62.3 mg g −1 , respectively. The adsorption kinetics conformed to the pseudo-second-order kinetic equation. The effect of temperature on the adsorption capacity was not significant. Physical diffusion and chemical adsorption coexist in the process of adsorption of metal ions by straws, and chemical adsorption is dominant, and the effect of physical diffusion on the chemical adsorption rate can be neglected. It can be seen from the experimental results that the treatment of chromium-containing wastewater by using cheap and easily available wheat straw and corn straw had a remarkable effect. The adsorbed straw could be completely desorbed and had excellent recyclability, indicating that the straws are ideal adsorbents.

Maize Stalk Material for On-Site Treatment of Highly Polluted Leachate and Mine Wastewater

“…At the same time, all Qe (mg/g) values determined for Cu(II) were lower than those for Fe(III) that is 0.056 to 0.133 mg/g. Overall, this study demonstrates that maize stalk may be used in practical applications for wastewater depollution containing mostly the two metal ions studied, showing very good performance as compared with other wastewater treatment materials, as can be observed in detail in Table 1 in the Supplementary Materials [12][13][14][15][16][17][18][19][20][21][22][23]. All batch adsorption experimental results are presented in Figure 2.…”

“…Consequently, the functional group of these compounds proves affinity for wastewater metallic ions that may be retained by various mechanisms such as ion exchange or inside pores by diffusion [ 11 ]. Moreover, in recent years, many natural potential bio-sorbents suitable for metal removal using batch mode from aqueous solutions have been reported in the literature [ 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 ]. Chemical modification improves the adsorption capacity of cellulosic material.…”

“…Studying the Langmuir equation, the maximum adsorption capacity of wheat straw for Cr(VI) and Cr(III) was determined as being 125.6 and 68.9 mg/g, respectively. Approximate values of adsorption capacity were obtained for corn straw by applying the same experimental model [ 22 ]. Štefušová et al studied the removal of Pb(II) and Cd(II) on wheat straw and rapeseed residues.…”

Preparation of bio-absorbents by modifying licorice residue via chemical methods and removal of copper ions from wastewater

“…As the concentration increased, the driving force for adsorption increased, which lead to a raising in adsorption capacity. When the initial concentration increased further, the adsorbed active sites tended to be saturated (Chen et al 2020). The order of adsorption concentrations of the three bio-adsorbents was as follows: LR-NaOH(100 mg/L).LR-Na 2 CO 3 (80 mg/L).LR-CA(60 mg/L).…”

Pt Nanoparticles Embedded in KOH-Activated Soybean Straw as an Efficient Catalyst toward Benzene Oxidation

“…1 According to 2019 statistics by the Ministry of Agriculture of China, various crops had produced more than 600 million tons of straw. 2 However, after the annual harvest, a large amount of straw is discarded or directly burned in the open field, resulting in a waste of resources and environmental pollution. 3 Therefore, the rational utilization of straw has become an inevitable environmental protection trend and sustainable development strategy.…”