Waste Diatomite Research Articles

Magnesium oxide modified diatomite waste as an efficient adsorbent for organic dye removal: adsorption performance and mechanism studies

ABSTRACTMagnesium oxide modified diatomite waste (MgO-DW) was successfully synthesized. The adsorption behaviors of methylene blue (MB) and acid orange (AO) over MgO-DW were studied. The samples involved were characterized by Fourier transform infrared, scanning electron microscopy, energy dispersive spectrometer, Brunauer Emmett Teller, X-ray diffraction, and zero point of charge analyses. Experimental factors including contact time, adsorbent dosage, pH, and initial dye concentration were explored. Maximum adsorption capacity of MgO-DW for MB (pH 11.0) and AO (pH 2.0) was 25.02 and 35.13 mg/g at 303 K, respectively. The results showed that Langmuir isotherm and pseudo-first-order kinetic models fitted the experimental data better. Regeneration tests confirmed that MgO-DW has promising potential in reusability.

Yeast protein derived hierarchical mesoporous carbon for symmetrical capacitor with excellent electrochemical performances

Abstract Converting waste bioresources into energy materials is a significant project in the increase of additional economic value. We herein report beer yeast protein derived hierarchical mesoporous carbon and successfully used as the electrode material on symmetrical capacitor. The preparation of hierarchical mesoporous carbon is made by carbonizing waste diatomites after adsobing beer yeast protein in the process of beer filteration. The porous diatomites play the role of constructing three dimensional porous carbons. Deep pyrolysis of diatomite at high temperature enables readily to transfer the adsorbed yeast protein into porous carbon. The hierarchical mesoporous carbon obtained at 800 °C show the single electrode capacitance of up to 300 F g−1. The assembled symmetrical capacitor delivers a high initial capacitance of 170 F g−1 at a current density of 1 A g−1 in 6 M KOH electrolyte. It still retains 84% capacity retention even after 10000 times cycling. We believed that the simple and effective strategy will provides a new application direction for the reutilization and the improved additional economic value of waste diatomite from brewery.

Cuprous Oxide-Modified Diatomite Waste from the Brewery Used as an Effective Adsorbent for Removal of Organic Dye: Adsorption Performance, Kinetics and Mechanism Studies

Cuprous oxide-modified diatomite waste (Cu2O-DW) as a low-cost and effective adsorbent was prepared via a hydrothermal route combined with acid-alkali treatment. The microstructure and surface properties of the obtained Cu2O-DW composite was characterized by Brunauer-Emmett-Teller, scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. The adsorption behaviors of three different types of dyes such as cationic dye methyl blue (MB), anionic dye acid orange (AO), and reactive dye reactive yellow (RY) onto the as-prepared Cu2O-DW were investigated. Several experimental parameters such as contact time, adsorbent dosage, initial dye concentration, and initial pH values were systematically estimated. The experimental results indicated that as-prepared Cu2O-DW have a better adsorption performance for MB, AO, and RY. Moreover, the kinetic and isotherm models were also used to account for the adsorption mechanism of dye molecules onto Cu2O-DW. The results demonstrated that three different dyes are all fitted well with pseudo-first-order kinetic model. Additionally, the Langmuir and Freundlich isotherm model is more suitable for describing the adsorption process of RY and MB on the as-prepared Cu2O-DW, respectively, and the AO adsorption is propitious to the D-R isotherm model. The value of adsorption energy (E < 8 kJ mol−1) confirmed that the physical adsorption is dominator during the adsorption process. The findings of the study demonstrated that the synthesized Cu2O-DW composite can be a promising adsorbent for the removal of organic dyes from wastewater and it provided a sustainable development method for cycling the diatomite waste from the brewery.

Characteristics of porous ceramics prepared from sandblasting waste and waste diatomite by co‐sintering process

The purpose of this research is to recycle sandblasting waste from the surface treatment process of solar cell industry to replace waste diatomite (with a replacement ratio of 0–20%) to make water‐retention porous ceramics, and adopts the method of molding by semi‐dry pressing under a pressure of 5 MPa, as the heating temperature fluctuated between 1000, 1100, 1200, and 1270°C. With a heating rate of 5°C/min, the heating process continued for 120 minutes. The sintered samples were then examined to determine whether its mechanical properties were met the CNS 382 R2002 Brick Criteria in terms of compressive strength (&gt;3 MPa); while FTIR, and MIP instruments were used to measure the changes in the sintered samples according to pore size and total pore volume. The results indicated that the waste diatomite and sandblasting waste consisted of quartz, and porosities of porous ceramics with sandblasting waste about higher than 58.5–64.7%, water absorption of about 72.2–92.2%, and compressive strength of about 2.4–7.3 MPa can be produced using a porous ceramics of raw materials. The porous ceramics samples with 0–20% sandblasting waste prepared at the heating temperature of above 1100°C meet the Standards for Japan Interlocking Block Pavement Engineering Association (compressive strength &gt; 3 MPa, water absorption &gt; 70%). Moreover, the thermal conductivity of cement paste was 0.57 W/m.K, which was significantly higher than 0.28–0.49 W/m.K of porous ceramics with sandblasting waste, the porous ceramics have good heat insulation effects. © 2018 American Institute of Chemical Engineers Environ Prog, 38: 321–328, 2019

Preparation of adsorption material through calcining waste diatomite for treatment of dye water

Preparation of adsorption material through calcining waste diatomite for treatment of dye water

Characteristics of water-retaining porous ceramics with sandblasting waste

The study focuses on the characteristics of water-retention porous ceramics with sandblasting waste. Recycling of sandblasting waste collected from the surface treatment process in the solar industry. Sand blasting waste is mainly composed of Al2O3, and also contains very small portion of silicon and SiC. Water-retaining porous ceramic (WRPC) samples, comprising waste diatomite and sandblasting waste, with excellent humidity control performance were prepared. The appearance and structural properties of the samples were investigated through analysis of water absorption and compressive strength, X-ray diffraction, and scanning electronic microscopy. Moreover, the water retention performance levels of the samples at various heating temperatures were investigated. The WRPC samples prepared at the heating temperature of 1,270°C meet the Standards for Japan Interlocking Block Pavement Engineering Association (compressive strength>3MPa, water absorption>70%). At high heating temperatures, the quartz of the WRPC samples completely changed to cristobalite, thus affording the WRPC samples favorable chemical properties and heat stability. When the WRPC samples were sintered at high temperatures (1,200–1,270°C), because of the driving force of sintering, the Scanning Electron Microscope (SEM) micrographs exhibited neck growth. The samples featured high compressive strength, low water absorption, and high water-retention performance. The results revealed that the WRPC samples could maintain a good water-retention performance for 10–15h and better than in the foamed glass material (4h). WRPC samples containing 5–20% sandblasting waste exhibited excellent water-retention performance at various heating temperatures.

Utilization of industrial waste as a novel adsorbent: Mono/competitive adsorption of chromium(VI) and nickel(II) using diatomite waste modified by EDTA

The adsorption of Cr(VI) and Ni(II) using ethylenediaminetetraacetic acid‐modified diatomite waste (EDTA‐DW) as an adsorbent in single and binary systems was investigated. The EDTA‐DW was characterized using various analytical techniques, including Fourier transform infrared spectroscopy, thermogravimetric analysis, Brunauer–Emmett–Teller measurements, X‐ray diffraction, scanning electron microscopy and energy‐dispersive spectrometry. The adsorption experiment was conducted by varying pH, adsorbent dosage, initial concentration and temperature. In the single system, the sorption data for Cr(VI) fitted the Langmuir isotherm, but the Ni(II) adsorption data fitted well the Freundlich isotherm. The maximum sorption capacity of Cr(VI) and Ni(II) was 2.9 mg g−1 at pH = 3 and 3.64 mg g−1 at pH = 8, respectively. The kinetic data for both Cr(VI) and Ni(II) followed well the pseudo‐second‐order kinetic model in single and binary systems. Meanwhile, the extended Langmuir and extended Freundlich multicomponent isotherm models were found to fit the competitive adsorption data for Cr(VI) and Ni(II). In addition, in the binary system, the existence of Ni(II) hindered the adsorption of Cr(VI), but the presence of Cr(VI) enhanced the removal of Ni(II). This study provides some realistic and valid data about the usage of modified diatomite waste for the removal of metal ions.

Experimental Study on Waste Diatomite Modified Asphalt Mixture

Used as beer filter aid, diatomite is low in utilization rate and environmentally-harmful after it lost its efficacy and was piled up in outdoor environment. In order to recycle waste diatomite, this study conducted heating curing for waste diatomite under 105 ℃ , so as to get rid of moisture, and then, through crushing, grinding, and heat activation under 300 ℃ , the processed diatomite was added to asphalt mixture in an appropriate amount. According to orthogonal experimental method, the effect of activated waste diatomite on asphalt mixture’s stability and durability was tested through mix design and performance test on a series of asphalt mixture, providing a new method and an approach for diatomite recycling.

Utilization of industrial wastes for preparation of high performance ZnO/diatomite hybrid photocatalyst

The enhanced photocatalytic activity of ZnO was successfully obtained by immobilized ZnO particles on diatomite support using simple impregnation and calcination method. It is interesting that both starting materials (ZnO and diatomite) used for hybrid photocatalyst synthesis in this work were prepared from industrial wastes. A zinc-dust waste derived from hot-dip galvanizing process was used for synthesis of zinc oxide particles and diatomite waste derived from brewery industries was used as a porous substrate. Effects of preparation pH, loading amount of zinc oxide and calcination temperature on the photocatalytic activity for degradation of methylene blue solution of ZnO-immobilized hybrid photocatalyst products were investigated. It was demonstrated that the enhancement in photodegradation performance of ZnO caused by the high absorbability of diatomite support. The hybrid photocatalyst sample prepared by precipitation at pH 10 loading with 20wt% of ZnO on diatomite and calcination at 600°C showed the highest methylene blue degradation efficiency of about 85.90% under UV light irradiation for 2h.

Combination of Mechanical and Chemical Methods to Recover Waste Diatomite

Combination of Mechanical and Chemical Methods to Recover Waste Diatomite

Oily diatomite and galvanic wastes as raw materials for red ceramics fabrication

This work focused on the applicability and viability analysis of oil-contaminated diatomite waste and other two industrial residues (galvanic sludge and glass waste materials) in red ceramic fabrication. Red ceramic samples were produced varying the amount of waste materials. Diatomite content, galvanic sludge, and glass wastes in new materials ranged from 25% to 35%, 20% to 25%, and 5% to 20%, respectively. Natural clay was present by 30%. Mixtures of initial components were hydrated, compacted, dried and baked with different temperatures (950°C, 1000°C, 1050°C, and 1100°C) during 6h. The materials were analyzed by Scanning Electronic Microscopy (SEM), Electron Dispersive Spectroscopy (EDS), X-Ray Fluorescence Spectroscopy (XRF) and X-Ray Diffraction (XRD) techniques. Red ceramic samples were subjected to flexion resistance tests. High resistance, low dilatation values, water absorption, solubility and leaching of heavy metals could be observed in the obtained ceramic samples. Those outcomes can be explained by melting of some crystal structures of raw components (completely of Illite and partly of Quartz) and partial transition to amorphous glassy formations, well visible by SEM micrographs. The developed materials can be highly economically attractive because of the utilization of industrial wastes to produce construction materials. The wide-scale use of the method can be environmentally effective.

Water Retention Characteristics of Porous Ceramics Produced from Waste Diatomite and Coal Fly Ash

Abstrac t—This study examines potential waste diatomite and coal fly ash reuse to prepare water absorption and retain porous ceramics. The operating conditions are constant pressure (5 MPa), sintering temperature (1000-1270°C), sintering time (2 h), waste diatomite containing coal fly ash at different proportions (0-20%), respectively. The porous ceramic samples containing coal fly ash show low thermal conductivity properties (0.278-0.349 W/mK), probably owing to the more pores than those in the concrete (1.458 W/mK). Water release (t1/2 value) by the porous ceramic samples is decelerated by porous ceramic samples containing coal fly ash, due to the synergy effect of high water absorption by the coal fly ash and better than in the foamed glass material (4 h). Porous ceramic samples containing coal fly ash is highly promising for use in water absorption and retention applications.

Porous Ceramic Characteristics Sintered from Waste Diatomite and Sodium Silicate Sand

Porous Ceramic Characteristics Sintered from Waste Diatomite and Sodium Silicate Sand

Water absorption and retention of porous ceramics cosintered from waste diatomite and catalyst

This study examines potential waste diatomite and catalyst reuse to prepare water absorption and retain porous ceramics. The operating conditions are constant pressure (5 MPa), sintering temperature (1000–1270°C), sintering time (2 h), waste diatomite containing waste catalyst at different proportions (0–20%), respectively. The porous ceramic samples containing waste catalyst show low thermal conductivity properties (0.278–0.349 W/mK), probably owing to the more pores than those in the concrete (1.458 W/mK). Water release (t1/2 value) by the porous ceramic samples is decelerated by porous ceramic samples containing waste catalyst, due to the synergy effect of high water absorption by the waste catalyst and better than in the foamed glass material (4 h). Porous ceramic samples containing waste catalyst is highly promising for use in water absorption and retention applications. © 2012 American Institute of Chemical Engineers Environ Prog, 32: 640–648, 2013

Characteristics of Porous Ceramics Produced from Waste Diatomite and Water Purification Sludge

In this investigation, samples of waste diatomite and water purification sludge were subjected to a constant pressure of 5 MPa, sintering temperatures of 1000°C to 1270°C, and a sintering time of 2 hours to determine the suitability of the materials for the development of porous ceramic products. The percentage of water purification sludge mixed in the waste diatomite ranged from 0% to 20%. Under the operating conditions just described, a homogeneous melt with a viscosity that allowed the samples to be shaped was obtained. Microstructures, crystal structures, and volumes of the pores of the ceramic samples were then determined by X-ray diffraction, scanning electron microscopy, and mercury intrusion porosimetry, respectively. When the heating temperature was 1270°C, porous ceramic samples of diatomite containing 20% water purification sludge had a density of 0.97 g/cm3, a porosity of 49.9%, a water absorption of 51%, a shrinkage of 15.3%, and a high compressive strength (18.3 MPa). When heated to this temperature, sintered samples contained pores of approximately 2.5 μm to 3 μm, and they yielded a small peak in around 0.3μm to 2 μm. In summary, porous ceramics samples of 80% diatomite and 20% water purification sludge have favorable mechanical properties and therefore may be utilized in several applications, particularly as a water-retaining material in pavements.

Feasibility of recycling waste diatomite and fly ash cosintered as porous ceramics

This investigation demonstrates the feasibility of using diatomite and coal fly ash as alternative raw materials in the production of the porous ceramics. The following operating conditions are set for sintering process; a constant pressure of 5 MPa, a sintering temperature of 1000–1270°C, a sintering time of 2 h, and various proportions (0–20%) of coal fly ash in waste diatomite. This investigation concerns the effects of heating temperature and proportion of fly ash on the characteristics of porous ceramics that are formed from a mixture of fly ash and waste diatomite. Heat‐treated samples were analyzed by X‐ray diffraction (XRD), scanning electron microscopy (SEM), and mercury intrusion porosimetry (MIP), which supported the following conclusions. When the heating temperature was increased above 1270°C, the compressive strength of the ceramics was between 5.85 and 15.8 MPa. When the amount of coal fly ash exceeds 20%, the porosity of the porous ceramics decreases sharply with increasing temperature from 61.6% obtained at 1100° C to 52.9% obtained at 1270° C. When heating to 1270° C, the pore sizes of sintered samples ∼2.5–3 μm, and a smaller peak around 0.3–2 μm. Adding coal fly ash to the porous ceramics increased their compressive strength, indicating that waste diatomite and coal fly ash can indeed be 100% recycled and reused as porous ceramics. © 2011 American Institute of Chemical Engineers Environ Prog, 32: 25–34, 2013.

Removal of basic dye (methylene blue) from wastewaters utilizing beer brewery waste

In the work, the beer brewery waste has been shown to be a low-cost adsorbent for the removal of basic dye from the aqueous solution as compared to its precursor (i.e., diatomite) based on its physical and chemical characterizations including surface area, pore volume, scanning electron microscopy (SEM), and non-mineral elemental analyses. The pore properties of this waste were significantly larger than those of its raw material, reflecting that the trapped organic matrices contained in the waste probably provided additional adsorption sites and/or adsorption area. The results of preliminary adsorption kinetics showed that the diatomite waste could be directly used as a potential adsorbent for removal of methylene blue on the basis of its adsorption–biosorption mechanisms. The adsorption parameters thus obtained from the pseudo-second-order model were in accordance with their pore properties. From the results of adsorption isotherm at 298 K and the applicability examinations in treating industrial wastewater containing basic dye, it was further found that the adsorption capacities of diatomite waste were superior to those of diatomite, which were also in good agreement with their corresponding physical properties. From the results mentioned above, it is feasible to utilize the food-processing waste for removing dye from the industrial dying wastewater.

Eco-Materials for Developing Countries

The concept of eco-materials has been introduced to encourage the development of materials that are not only harmless to the global environment but also exert minimal burden on the planet during their production, by making efficient use of raw materials and being highly recyclable. Accordingly, studies are being conducted worldwide seeking to evolve eco-materials for sustainable development in the 21st century. This paper presents findings of research undertaken to assess the viability of re-engineering uncollected garbage (municipal waste) as well as available local materials in Kenya for use as sustainable construction materials. Experimental work involved compressive and flexural tests on mortar prisms, as well as compressive and indirect tensile tests on concrete cylinders. The main variables were the type of cement (eco-cement and ordinary Portland cement), and type of additive or supplementary material (municipal waste ash, quarry dust, anthill, coral stone, diatomite and silica sand) added in various percentages as a partial replacement of cement or fine aggregate. Results obtained show the apt performance or superior behavior of mortar or concrete made from the tested additives in comparison to the control mixes, thus indicating the enormous potential of municipal waste (garbage) ash and natural local materials in Kenya for use as supplementary eco-materials in cement and concrete production.