Solution combustion synthesis of calcium aluminate nanocomposite using coffee husk extract as green fuel and its application in adsorptive amputation of anionic dyes

Abstract

Solution combustion synthesis of calcium aluminate (CaAl 2 O 4 ) nanocomposite using coffee husk extract and its adsorption capacity for removal of Congo red (CR) and Indigo carmine (IC) are reported. Physiochemical properties of adsorbent were studied by PXRD, SEM, TEM and point of zero charge. Batch adsorption studies were conducted to study the effect of adsorbent dosage, pH, contact time, initial dye concentration and temperature on adsorption efficiency of coffee husk derived calcium aluminate nanocomposite (CHCA). Among the isotherms used, Langmuir model explained best the equilibrium data and the maximum monolayer adsorption capacity was found to be 377 and 135 mg/g for CR and IC, respectively. Mass transfer analysis indicated adsorptive removal of dyes was controlled by both external and internal diffusion. Pseudo-first-order model fitted best with experimental kinetic data and adsorption efficiency increased with an increase in the initial bulk concentration of CR and IC. Thermodynamic analysis indicated that adsorption of CR and IC on CHCA is feasible, spontaneous and exothermic in nature. The magnitude of enthalpy and heat of adsorption suggested that the adsorption is physical in nature. The present study explores the potential of coffee husk extract, an agro-based bio-waste, as a novel and eco-friendly fuel in the synthesis of CHCA and the synthesised nanocomposite as a potential adsorbent for the removal of synthetic dyes.

Process optimisation of methylene blue sequestration onto physical and chemical treated coffee husk based adsorbent

“…Kinetics analysis of the adsorption process explains the rate of uptake of adsorbent and also aids to determine the residence time of the adsorption. It is one of the important characteristics in defining the efficiency of adsorption [5]. The effect of time on adsorption of MB on SCH and NCH was carried out at experimental conditions: 25 mg/L, 0.3 mg/L of SCH and NCH dosage, pH 8, 50 ml of volume, 30 °C, and the time is varied between 0 and 120 min.…”

“…Approximately 10-15% of the total dyestuff is utilised or released into the natural environment aesthetically unfavourable, and these recalcitrant and coloured dye molecules are not so easy to degrade biologically and are resistant to degrade on exposure to water, to light and also to various chemicals [3,4]. Due to the toxic, carcinogenic, mutagenic and allergic nature of dyes, the direct discharge of untreated dye effluent can cause hazardous effects on living systems [5]. Several physicochemical and biological methods such as ozonation, chemical coagulation, chemical and electrochemical oxidation, photocatalysis, adsorption, and aerobic and anaerobic digestion are widely used Electronic supplementary material The online version of this article (https ://doi.org/10.1007/s4245 2-020-2603-9) contains supplementary material, which is available to authorized users.…”

“…Among these methods, adsorption has emerged as an effective and economical alternative due to its ease of operation, simplicity of design, insensitivity to toxic substances and complete amputation of pollutants rather than getting degraded to hazardous intermediates [8,9]. The high cost and difficulty in regeneration are still concerned with the use of activated carbon, and it has motivated the research community to develop efficient and cost-effective alternative adsorbents for removal of dyes [5].…”

Preparation and Adsorption Properties of Soybean Dreg/Hydrocalumite Composites

“…The results showed that the adsorption process of CR by 30%BD-LDH4 followed the pseudo-second-order kinetic model. As shown by the results in Table , the adsorption process of CR by 30%BD-LDH4 was divided into three different stages . The straight line in the first stage did not pass through the origin, indicating that internal diffusion was not the only rate control step in the adsorption process.…”

“…The soybean dreg could be used as a cheap adsorption material since it contains rich oxygen-containing functional groups and has a loose and porous structure. − However, the specific surface area of the soybean dreg is small; therefore, its adsorption performance needs to be further improved. According to the previous literature, the main methods to improve the adsorption properties of biomass adsorbents included modification, carbonization, and preparation of composites. − Recently, combined with the advantages of biomass organic adsorption materials and traditional inorganic adsorption materials, the organic/inorganic composite adsorbents had attracted much attention. − For example, Abu-Danso et al found that the maximum adsorption capacities of clay/cellulose composites for Pb (II) and Cd (II) reach 389.78 and 115.96 mg·g –1 , respectively . Mirjavadi et al reported that the magnetic zeolite/cellulose nanofibers showed high adsorption capacity for the removal rate of Zn 2+ .…”