Properties of Matrix for Reducing Fine Dust According to Replacement Ratio of Bentonite

One of the global issues documented entails fine dust reduction, which has been experimented recently. In humans, fine dust is problematic because it causes diseases. This study employed the techniques of circulating fluid bed combustion boiler fly ash and blast furnace slag as binders. Regarding fine dust reduction, the study incorporated Bentonite, which exhibits adsorption features. Indeed, indoor air pollution arises from the dominance of fine dust. Some of the parameters that were examined included fine dust concentration, water absorption, density, flowability, compressive strength, and flexural strength. With an increase in the bentonite replacement ratio, there tends to be an increase in absorption, while the density increases. The bentonite’s porous nature has been perceived to account for this behavior. In this study, it was established further that as ben-tonite’s replacement ratio increased, there was a decrease in flowability. Additionally, there was an increase in the air content with an increase in bentonite’s replacement ratio. It was also noted that the fine dust’s adsorption performance for each minute increased with an increase in bentonite’s replacement ratio. The findings were attributed to the affirmation that with an increase in the porous bentonite’s replacement ratio, there tends to be an increase in fine dust amount adsorbed for each unique surface area. There is a need for further research in which experimentations need to focus on finishing materials and how indoor air quality could be improved.

Study on Adsorption Mechanism and Failure Characteristics of CO2 Adsorption by Potassium-Based Adsorbents with Different Supports

In order to obtain the adsorption mechanism and failure characteristics of CO2 adsorption by potassium-based adsorbents with different supports, five types of supports (circulating fluidized bed boiler fly ash, pulverized coal boiler fly ash, activated carbon, molecular sieve, and alumina) and three kinds of adsorbents under the modified conditions of K2CO3 theoretical loading (10%, 30%, and 50%) were studied. The effect of the reaction temperature (50 °C, 60 °C, 70 °C, 80 °C, and 90 °C) and CO2 concentration (5%, 7.5%, 10%, 12.5%, and 15%) on the adsorption of CO2 by the adsorbent after loading and the effect of flue gas composition on the failure characteristics of adsorbents were obtained. At the same time, the microscopic characteristics of the adsorbents before and after loading and the reaction were studied by using a specific surface area and porosity analyzer as well as a scanning electron microscope and X-ray diffractometer. Combining its reaction and adsorption kinetics process, the mechanism of influence was explored. The results show that the optimal theoretical loading of the five adsorbents is 30% and the reaction temperature of 70 °C and the concentration of 12.5% CO2 are the best reaction conditions. The actual loading and CO2 adsorption performance of the K2CO3/AC adsorbent are the best while the K2CO3/Al2O3 adsorbent is the worst. During the carbonation reaction of the adsorbent, the cumulative pore volume plays a more important role in the adsorption process than the specific surface area. As the reaction temperature increases, the internal diffusion resistance increases remarkably. K2CO3/AC has the lowest activation energy and the carbonation reaction is the easiest to carry out. SO2 and HCl react with K2CO3 to produce new substances, which leads to the gradual failure of the adsorbents and K2CO3/AC has the best cycle failure performance.

ADSORPTION ISOTHERM STUDIES OF BOD, TSS AND COLOUR REDUCTION FROM PALM OIL MILL EFFLUENT (POME) USING BOILER FLY ASH

Palm oil is one of the two most important vegetable oils in the world’s oil and fats market. The extraction and purification processes generate different kinds of waste generally known as palm oil mill effluent (POME). Earlier studies had indicated the possibility of using boiler fly ash to adsorb impurities and colour in POME treatment. The adsorption treatment of POME using boiler fly ash was further investigated in detail in this work with regards to the reduction of BOD, colour and TSS from palm oil mill effluent. The amount of BOD, colour and TSS adsorbed increased as the weight of the boiler fly ash used was increased. Also, the smallerparticle size of 425μm adsorbed more than the 850μm size. Attempts were made to fit the experimental data with the Freundlich, Langmuir and Dubinin-Radushkevich isotherms. The R2values, which ranged from 0.8974–0.9898, 0.8848–0.9824 and 0.6235–0.9101 for Freundlich, Langmuir and Dubinin-Radushkevich isotherms respectively, showed that Freundlich isotherm gave a better fit followed by Langmuir and then Dubinin-Radushkevich isotherm. The sorption trend could be put as BOD > Colour > TSS. The apparent energy of adsorption was found to be 1.25, 0.58 and 0.97 (KJ/mol) for BOD, colour and TSS respectively, showing that sorption process occurs by physiosorption. Therefore, boiler fly ash is capable of reducing BOD, Colour and TSS from POME and hence could be used to develop a good adsorbent for POME treatment.

Drying characteristics of biosludge from pulp and paper mills

Handling and disposal of biosludge has been a persistent problem for many pulp and paper mills primarily because of the material’s high moisture content and poor dewatering and drying characteristics. Most biosludge is landfilled or incinerated, and some is used as a soil amendment. To incinerate biosludge, the mills mix it with primary sludge, mechanically dewater the mixture to 15%–30% solids, and burn it with hog fuel in biomass boilers. For biosludge to burn effectively, however, it must be dewatered or dried to at least 30%–35% solids. A systematic study was conducted to examine the drying characteristics of biosludge collected from pulp and paper mills at various temperatures using a thermogravimetric dryer. The drying behavior of the tested biosludges was similar, adding fillers such as wood fines and biomass boiler fly ash to biosludge up to 30 wt% did not significantly affect the drying rate, higher organic content might make biosludge more difficult to dry, and increasing drying temperature significantly increases the drying rate as expected.