A comparative study of the adsorption of congo red dye on rice husk, rice husk char and chemically modified rice husk char from aqueous media

Abstract

<jats:p>Desirable cost and removal effectiveness of the adsorbents can be obtained by the use and modification of agricultural waste products. Therefore, in this study rice husk (RH), rice husk char (RHC) and chemically modified rice husk char (CMRHC) were prepared and used as adsorbents for the removal of Congo Red dye from aqueous media under different experimental conditions. It was observed that the adsorption of Congo Red dye was not only affected with the types of adsorbents used but also with other experimental variables such as time, adsorbent dose, dye concentration, pH and temperature. Thermodynamics study indicated that the adsorption of Congo Red dye on the three adsorbents is spontaneous and exothermic process. Kinetics data showed that the adsorption of Congo Red dye on these adsorbents follow pseudo-second order model better than the pseudo-first order model. Equilibrium adsorption data were tested with Langmuir, Freundlich, and Temkin adsorption isotherm models. It was observed that the equilibrium data of RH and RHC were found best fit to the Langmuir adsorption isotherm model whereas that of CMRHC was best fit to the Freundlich and Temkin models. CMRHC showed better efficiency compared to both RH and RHC.&#x0D; &#x0D; Bull. Chem. Soc. Ethiop. 2020, 34(1), 41-54.&#x0D; DOI: https://dx.doi.org/10.4314/bcse.v34i1.4</jats:p>

Coconut husk-raw clay-Fe composite: preparation, characteristics and mechanisms of Congo red adsorption

“…Popoola et al 5 also reported optimum pH 3 for removal of Congo red using synthesised coal graphene. Removal of Congo red dye onto the adsorbents is usually influenced by pH because pH influences polarity of the surface of adsorbents as well as ionisation and ionic mobility of Congo red 13 . Congo red has a bipolar characteristic and can behave as anionic and cationic compound in solution depending on the pH of the medium 5 .…”

“…Adsorptive elimination of recalcitrant dye molecules from contaminated water and wastewater is considered most effective and efficient because most of the adsorbent materials are low-cost, green and eco-friendly, easily available, renewable, and efficient 8 . Different materials that have been successfully employed for adsorption of Congo red from aqueous solutions include amino-functionalised silica gel 9 , activated carbon coffee waste 10 , bark of Pine 7 , clay–corn cob–FeCl 3 11 , Periwinkle shell activated carbon 12 , Ackee apple seed–bentonite composite 3 , modified rice husk char 13 , synthesised coal graphene 5 and Water hyacinth bark carbon 14 .…”

Characterization and Utilization of Sulphuric Acid and Bitter Leaf Extract Activated Carbon from Rice Husk for Zn(II) Adsorption

“…where R is the gas constant, T is the temperature in K and K e is the equilibrium constant given by Eq. (4) [41][42][43].…”

Effectivity of Indonesian Rice Husk as an Adsorbent for Removing Congo Red from Aqueous Solutions

“…Indonesia has many industries, such as plastics, textiles, pulps, papers, pharmaceuticals, and cosmetics that produce waste pollutants, such as dyes, that are released into the environment. The presence of dyes in aquatic systems can cause severe environmental problems (Saini, 2017;Vinsiah et al, 2017;Malik et al, 2020) These dyes are carcinogenic, nonbiodegradable, and toxic to humans and biota in environmental systems (Hassaan and Nemr, 2017;Yaseen and Scholz, 2019). Several methods for removing dyes from wastewater have been developed to decrease their impact on health and environment (Banerjee and Chattopadhyaya, 2017).…”

“…Thus, to increase this adsorption capacity, they should be activated by carbonization (Bamroongwongdee et al, 2019;Milla et al, 2013). Malik et al (2020) also reported comparative comparison of RH, RH char, and chemically modified RH used as adsorbents for the removal of the Congo red dye. This study reported that the adsorption capacities of the RH, RH char, and chemically modified RH char (CMRHC) are 1.58 mg/g, 1.28 mg/g, and 2.04 mg/g, respectively, for Congo red dye removal.…”