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Pesticide Use and Calibration
Published in L.B. (Bert) McCarty, Golf Turf Management, 2018
Activated charcoal (also called activated carbon) is often used to adsorb or deactivate organic chemicals such as pesticides. Activated charcoal has been used for many years to remove organic contaminants from wastewaters and in water purification systems. Since most pesticides are organic chemicals, activated charcoal can effectively be used to deactivate or “tie up” these products in soil. Once the pesticide has been adsorbed onto activated charcoal, it is biologically inactive and cannot cause injury to the turfgrass. Therefore, this product can be beneficial to turfgrass managers in the case of an accidental pesticide spill or where a pesticide needs to be inactivated for seeding or sprigging of turfgrasses. Due to its dark color and its consequent ability to absorb heat, activated charcoal is also used to artificially warm the soil to minimize the effects of light frosts or to allow earlier seeding of an area.
Sorption
Published in Igor Bello, Vacuum and Ultravacuum, 2017
Activated charcoal, also called activated carbon, is a porous material with very large internal surfaces,355 being as large as 1500 m2/g. Activated charcoal is made in powders, or granular and bead forms. It is prepared from organic precursors with high carbon contents, such as hard wood, charcoal, coconut shells, or synthetic polymers by carbonization processes with an assistance-poor oxidizer such as carbon dioxide. Depending on the precursor and processing, different types of activated charcoal can be prepared.
Vacuum Pumps
Published in Pramod K. Naik, Vacuum, 2018
Synthetic zeolites which are alumino-silicates of Na, K or Ca are most suitable sorbents for these pumps. Activated charcoal is a highly porous form of carbon, free from graphite, ash and any hydrocarbon residuals. Hardwoods and nutshells used as sorbents possess a structure of long, interconnected cellulose fibers built of groups of carbon, hydrogen and oxygen atoms arranged to form almost endless chain. Processing expels hydrogen and oxygen but carbon atoms probably retain their chainlike arrangement with some cross-linking but with many unsatisfied valencies. The resulting porosity includes passage of atomic dimensions. The material is cut into small pieces, freed from saw-dust and heated in closed but vented steel chamber at 500 to 700°C until all hydrocarbon is removed and no visible vapour evolution is observed. It is further treated at 600°C in dry vacuum and stored in vacuum. In an alternative method, passage of steam or CO 2 is passed through charcoal heated to 800°C to 1000°C. Activated charcoal Type 208-C is composed of coconut shell, steam activated charcoal and has an average pore diameter of 10 Å. Molecular sieves are synthetic, dehydrated, crystalline aluminosilicates. Their internal cavities are normally filled with water of crystallization. The unique property of the crystals being that the crystal structure remains unchanged even after the removal of the water of crystallization by heating and does not collapse. The internal cavities are interconnected by pores of uniform diameter. About half the volume of the crystal may consist of cavities that are available for sorption of such gases which are able to penetrate the interconnecting pores. Molecules of unsuitable size and shape are unable to pass through the pores so the zeolite structure acts as a sieve, excluding the larger and more awkwardly shaped molecules while permitting the smaller ones to enter. Molecular sieves are available in 1/8 inch or 1/16 inch cylindrical pellets. The following Table 6.1 gives details of the different types of molecular sieves that are available commercially.
Use of biochar as feed supplements for animal farming
Published in Critical Reviews in Environmental Science and Technology, 2021
Ka Yan Man, Ka Lai Chow, Yu Bon Man, Wing Yin Mo, Ming Hung Wong
Charcoal, activated charcoal and biochar are all types of pyrogenic carbonaceous matter. Table 1 shows the similarities and differences of the three products in terms of their raw materials, production processes, characteristics and applications. The three products are closely related and are differentiated mainly based on their applications. All three products share similar production conditions and properties. They are carbon-rich solids derived from carbon-rich biomass and produced by pyrolysis; that is, they are bio-based carbon materials. Charcoal made from wood-based materials has been used since ancient times as fuel for heating and cooking. Activated charcoal is derived from charcoal through activation by physical processes (using steam or carbon dioxide) or chemical processes (using an alkali or acid). Activation is an enhancement process to the charcoal, which promote its physico-chemical properties such as surface area. Biochar and activated charcoal are both derived from charcoal using similar or even the same production processes. Biochar is the precursor of activated charcoal (Azargohar & Dalai, 2006). It is used in water purification, syngas upgrading, biodiesel production, organic waste composting, and soil conditioning. It is also used for soil remediation because it improves water holding capacity, increases adsorption ability and improves microbial diversity. (Cha et al., 2016; Sanchez-Monedero et al., 2018).
The use of metal hydroxide sludge (in natura and calcined) for the adsorption of brilliant blue dye in aqueous solution
Published in Environmental Technology, 2019
Ana Maria Salgueiro Baptisttella, Andressa Aziz Diniz Araújo, Matheus Caldas Barreto, Vivian Stumpf Madeira, Mauricio Alves da Motta Sobrinho
Thus, the adsorption process is a physical method based on the separation due to molecular selectivity, considered by the literature as an efficient and economical method for the removal of dyes [10,11]. The main costs involved in the process of dye removal are normally centred around the costs of the adsorbent and its regenerative capacity [12,13]. Activated charcoal is commonly used as an adsorbent in adsorption processes, given its excellent surface area and adsorption capacity. However, the high costs for obtaining this product linked with its low regenerative capacity have motivated the search for new adsorbents [12,14].
Synthesis of activated charcoal from saw-dust and characterization for adsorptive separation of oil from oil-in-water emulsion
Published in Chemical Engineering Communications, 2018
V. K. Rajak, Sunil Kumar, N. V. Thombre, Ajay Mandal
Activated carbon has become technically prominent and the most extensively used adsorbents because of its notably high adsorptive capacity. Activated charcoal is efficiently used to remove toxic and biorefractive material such as, herbicides, oil and grease, insecticides, heavy metal ions, phenols, chlorinated hydrocarbons, chlorinated hydrocarbons, etc., which are present in many wastewater (Ansari and Masoudi, 2004; Austin and Shreve, 1985; Bansode et al., 2003). Karaer and Kaya (2016) synthesized a chitosan/activated charcoal composite for removal of methylene blue and reactive blue4 from aqueous solution. A huge production of ACs is demanded by the present technology with pertinent characteristics for each and every particular process. Usually, the AC which is used in any applications must have the competent adsorptive capacity and mechanical strength. In conjunction with all these specifications, the production cost should also be low. By controlling the process of carbonization, dehydration and oxidation of organic substances, AC can be obtained. Any materials that contain a high percentage of carbon can be converted into activated charcoal by physical or chemical techniques. However, the most commonly used ones in commercial practice are coal, wood, lignite, peats, and agricultural by-products such as almond shell, rice husks, coconut shell, etc. It has been stated that the coconut shell and apricot pits are the good sources of high grades of AC. Physical and chemical activation are the two processes by which ACs are prepared (Dąbrowski, 2001; Laine and Calafat, 1989; Ogasawara et al., 1987; Wigmans, 1989). The oxidation is preferred by a primary carbonization of raw material. AC is used to adsorb molecules from both liquid and gasses, which extensively depends upon the size of the adsorbate molecule, pore size distribution and the geometry of the adsorbent. Principally, the microporous carbon is used in adsorption from the gas phase, whereas, mesoporous carbon is used in the adsorption from the liquid phases. Mesoporous ACs are used in purification of drinking water, treatment of wastewater, processing of food and chemical and sweetener discolorization, whereas, microporous ACs are used in gasoline emission control, industrial gas treatment, gasoline emission control, and cigarette filters.