Rice Husk Ash For Removal Research Articles

Synthesis of SBA-16 mesoporous silica from rice husk ash for removal of Rhodamine B cationic dye: Effect of hydrothermal treatment time

Recently, the use of silica-containing wastes has gained popularity as an excellent pathway to prepare mesoporous silica materials for applications of adsorption, catalysis and energy. Hence, this report aimed to prepare SBA-16 mesoporous silica samples derived from rice husk ash under varying times during hydrothermal treatment (viz., 24 and 48 h) and named as SBA-16–24 h and SBA-16–48 h. FE-SEM, TEM, XRD, FTIR, Raman and N2 gas adsorption at − 196°C tools were performed to explore the formation of SBA-16. Rhodamine B (RhB) dye uptake from aqueous solutions by both samples was determined by equilibrium isotherms and kinetics. Effects such as pH, dye initial concentration, temperature and contact time were investigated. Results revealed the successful preparation of SBA-16 with an amorphous, ordered mesoporous structure and a higher total surface area of 461 m2/g for SBA-16–48 h obtained during a longer time of hydrothermal treatment. Increasing the time of hydrothermal treatment to 48 h decreased the average particle sizes of SBA from 50–40 nm to 20–10 nm with enhancing the total surface area, mesopore volume and amount of Si-O-Si groups. Equilibrium adsorption isotherms were fitted better by the Langmuir model than the Freundlich Temkin and Dubinin-Radushkevich models. The maximum adsorption capacity calculated from Langmuir model showed that SBA-16–48 h featuring the larger capacity of about 166.7 mg/g at pH 6. Pseudo-second order kinetic is found to be more suitable to describe the adsorption. Negative values of ΔH0 and ΔS0 thermodynamic parameters affirmed that the adsorption of RhB dye is an exothermic and spontaneous process over prepared mesoporous silica. Conclusively, the investigated SBA-16–48 h is a promising adsorbent for effective removal of basic dyes from their aqueous stream.

Evaluation of Adsorptive Characteristics of Cow Dung and Rice Husk Ash for Removal of Aqueous Glyphosate and Aminomethylphoshonic Acid

Glyphosate (GLY) is a major herbicide used throughout the world, and its continuous application has become an environmental issue. Adsorption is an important mechanism for removing organic contaminant in water. The present study characterized cow dung (CD) and rice husk ash (RHA), and determined the adsorption-desorption of GLY and its metabolite, aminomethylphoshonic acid (AMPA), on to them. The results revealed that both CD and RHA were alkaline and had no or low content of arsenic, cadmium, chromium and lead. The CD had lower surface area (13.104 mg2g−1) than RHA (21.500 m2g−1). The CD contained amines, phenol, ethers and carboxylic functional groups, while in addition to carboxylic and ether, RHA contains siloxane. Both CD and RHA had high affinities for GLY and AMPA. The Freundlich sorption coefficient (Kf) on AMPA were 2.915 and 2.660 for CD and RHA, respectively, while the values on GLY were 1.168 and 1.166 (mg g−1) for CD and RHA, respectively. Desorption of GLY only occurred at lower concentrations, while no desorption of AMPA was recorded, indicating their strong adsorption on CD and RHA. Considering their availabilities and affordable prices, both CD and RHA can be recommended as economical adsorbent for the removal of GLY and AMPA.

The study of adsorption efficiency of rice husk ash for removal of phenol from wastewater with low initial phenol concentration

This research work aimed to assess the adsorption efficiency of rice husk ash for removal of phenol from wastewater. The authors studied the morphology and characterization of rice husk ash using SEM, FTIR, XRD and BET analyzers and carried out the batch experiments to evaluate the removal percentage of phenol with variation of pH (3–11), adsorption time (30–270 min), adsorbent dose (0.5–4.0 gm/L), phenol concentration (5–20 mg/L) and temperature (25–35 °C). It was observed that the maximum removal reached as high as 95%. The testing of kinetic models showed that the second-order model was better than the first-order model. Elovich model showed that the adsorption process was chemical, Reichenberg model showed that adsorption occurred because of film diffusion, Furusawa and Smith model showed that phenol moved faster from bulk to solid stage, Boyd model indicated that the process supported chemisorptions, and Fick’s model implied that film and intraparticle diffusion took 45 min and 135 min, respectively. Testing of isotherm models indicated that Langmuir, Freundlich and Temkin models were all supportive of equilibrium data. The Dubinin–Radushkevich isotherm indicated that the process was explained by feeble physical adsorption. The isothermal study indicated that the process was random, endothermic and spontaneous. Although some studies had been done for removal of phenol using rice husk ash in the past, this research had covered the extensive works on the characterization of the adsorbent, extent of phenol removal with the variation of several process variables, and testing of several models in the areas of kinetics, isotherms, and thermodynamics. Further, the novelty of this research was that the experiments were carried out for treatment of wastewater exclusively with low initial phenol concentrations so that the results can be effectively applied in several small- and medium-scale industries at lesser costs, particularly in the Third World countries.

TiO2-zeolite photocatalysts made of metakaolin and rice husk ash for removal of methylene blue dye

In this study, synthesized zeolites were performed by solvothermal method using metakaolin and rice husk ash as starting materials. The TiO2-zeolites photocatalysts obtained from the solvothermal method was compared with that obtained from impregnation method. The synthesized products were characterized using X-ray Fluorescence spectrometer (XRF), X-ray diffraction (XRD), scanning electron microscopy (SEM), the Fourier transform infrared (FTIR), ultraviolet -visible spectroscopy (UV–vis), particle size analyzer and surface area measurement. The results showed that the incorporation of TiO2 in a form of transparent titanium solution into zeolites obtained from solvothermal method was very similar to that obtained from impregnation method confirmed by their mineralogical compositions, microstructures and specific surface areas. The adsorption and degradation efficiency of the TiO2-zeolites photocatalysts obtained from solvothermal method of 97.32% was slightly lower than 99.43% of impregnation method. In addition, the synthesized TiO2-zeolites photocatalysts showed a greater adsorption and degradation of methylene blue than pure zeolites and pure TiO2 anatase.

Application of polyaniline nanocomposite coated on rice husk ash for removal of Hg(II) from aqueous media

In this study, preparation of polyaniline (PAn) and its nanocomposite containing rice husk ash (RHA) was discussed, and their capability to removal of Hg(II) from aqueous solution was studied. Polyaniline (PAn) synthesized chemically in the presence of potassium iodate as an oxidant, coated on rice husk ash via cast method. The removal of Hg(II) was investigated using polyaniline, rice husk ash and polyaniline/rice husk ash nanocomposite, respectively. The products were investigated in terms of morphology and chemical structure with scanning electron microscopy (SEM) and Fourier-transform infrared spectroscopy (FTIR), respectively. Batch studies were performed to evaluate the influence of various experimental parameters like pH, adsorbent dosage, contact time and the rotating speed. Optimum conditions for mercury removal were found to be pH 9, adsorbent dosage of 10 g/L, equilibrium time 20 min and rotating time 400 rpm.

PENENTUAN WAKTU KONTAK DAN pH OPTIMUM PENYERAPAN METILEN BIRU MENGGUNAKAN ABU SEKAM PADI

Dyes are widely used for colouring in textile industries, significant losses occur during the manufacture and processing of the product, and these lost chemical are discharged in surrounding effluent. Adsorption of dyes is an effective technology for treatment of wastewater contaminated by the mismanaged of different types of dyes. In this research, we investigated the potential of rice husk ash for removal of methylene blue dyeing agent in aqueous system. The aim of this research is to find out the optimum contact time and pH on the adsorption of methylene blue using rice husk ash. Batch kinetics studies were carried out under varying experimental condition of contact time and pH. An adsorption equilibrium condition was reached within 10 minutes and the optimum condition for adsorption was at pH 3. The adsorption of methylene blue was decreasing with decreasing the solution pH value.