Application of ultrasound modified corn straw as adsorbent for malachite green removal from synthetic and real effluents

Abstract

This work aimed to study the removal of malachite green dye from wastewaters through adsorption using raw corn straw (RCS) and ultrasound-assisted modified corn straw (MCS). RCS and MCS were prepared and characterized in detail. The characterization indicated that RCS and MCS presented favorable structures for malachite green adsorption and that the ultrasound treatment provided a disorganization of the adsorbent's crystalline regions and also caused the formation of cavities and protuberances. The adsorption study was performed by equilibrium isotherms, kinetic curves, thermodynamic parameters, and application in real effluents composed of dye mixtures and inorganic compounds. The Elovich model was suitable for the adsorption kinetics and the Freundlich model was appropriate to represent the equilibrium. The maximum experimental adsorption capacities were 200 mg g for RCS and 210 mg g for MCS, obtained at 328 K. MCS was more effective than RCS to treat real effluents, attaining around 92% of color removal.

Adsorption of Hexavalent Chromium Simulated Effluent Using Fly Ash From Coal Gasification: Equilibrium, Kinetic and Thermodynamics

“…The value of Δ𝐻 is negative, from which it can be inferred that the Cr (VI) adsorption is an exothermic process, and that the temperature reduction improves the adsorption capacity [7]. In relation to Δ𝑆, the positive value found represents an increase in the randomness of the system during the adsorption process of Cr (VI) [22]. This behavior was obtained by Carvalho et al [29],…”

“…It was observed that the isotherms are favorable for the five temperatures. The inclination increasing with the temperature shows that even at higher initial Cr (VI) concentrations, the removal percentage is high, and this type of isotherm profile indicates that the adsorbent has several available sites for adsorption [22]. The specific surface area and pore volume of the fly ash presented in Table 1 were 18.82 m².g -1 and 0.036 cm³.g -1 , respectively.…”

Equilibrium, Kinetic, and Thermodynamic Studies of Cationic Dyes Adsorption on Corn Stalks Modified by Citric Acid

“…Our preliminary results showed that adsorption of cationic dyes on CS-C had maximum values at pH = 6.0-10.0, while at lower pH values, the adsorption of cationic dyes on CS-C was decreasing (the figure is not shown). It was also taken into account that according to [4], the cationic dyes removal is only by adsorption at pH = 6, and in an alkaline environment (pH range between 8.0 and 11.0), the color change of the dye solution occurs due to a chemical reaction between the cationic dye and OH-ions. Therefore, all adsorption experiments for dye removal using CS-C adsorbent were carried out at a pH value of 6.0.…”

“…The presence of a very small amount of dye (<1.0 mg/L) can markedly color the water and have a serious impact on its quality and the transparency of water bodies, rendering them unfit for the aquatic environment [3]. According to [4], industrial textile effluents of dyeing stages consist of 10-50 mg L −1 of cationic dyes. The removal of dyes from wastewater is important in protecting the environment because they usually have a complex aromatic structure that makes them stable to light, heat, and oxidizing agents while being recalcitrant to biodegradation [3].…”

Efficient adsorption of Malachite Green from water by activated carbon of Date trunk fiber

“…These toxic dyes become the cause of serious damage to the human health like kidney failure, damage of liver ,central nervous system ,brain ,reproductive system, hemorrhage, skin related complications etc. Similarly, these toxic dyes and their biodegradable products are reported to be cancer causing, mutagenic and teratogenic for many living species including human [9][10]. Most importantly it has been reported that dyes can become the cause of soil infertility as it cause of the death of many beneficial soil organisms [11].…”