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Humidity Sensor Based on Alum–Fly Ash Composite
Published in Amit Sachdeva, Pramod Kumar Singh, Hee Woo Rhee, Composite Materials, 2021
Amit Sachdeva, Shri Prakash Pandey, Pramod K. Singh
The most common alum is the double sulfate of potassium and aluminum, K2Al2(SO4)4.24H2O, a white crystalline powder that is readily soluble in water. It is used in curing animal skins. Other alums are used in papermaking and to fix dyes in the textile industry. The raw material of manufacture of common alums is alum rock, composed chiefly of alunite or alum stone. Alum is also made from alum shale, which is either allowed to decompose by exposure, or roasted. During the process, free sulfuric acid is formed, which acts upon the clay, producing aluminum sulfate, which is then dissolved out. Potassium sulfate or ammonium sulfate is added to the solution to produce potash alum or ammonia alum.
Water Treatment
Published in Frank R. Spellman, The Science of Water, 2020
Coagulation is the reaction between one of these salts and water. The simplest coagulation process occurs between alum and water. Alum or aluminum sulfate is made by a chemical reaction of bauxite ore and sulfuric acid. The normal strength of liquid alum is adjusted to 8.3%, while the strength of dry alum is 17%.
Aluminum
Published in Brian D. Fath, Sven E. Jørgensen, Megan Cole, Managing Global Resources and Universal Processes, 2020
Bernhard Wehr Johannes, Cardell Blamey Frederick Paxton, Martin Kopittke Peter, William Menzies Neal
Due to its corrosion resistance, light weight, and excellent thermal and electrical conductivity, the metal is extensively used in the building and construction industries (window frames, doors, external cladding, A/C ducts, thermal insulation), automotive (engine blocks, car bodies), shipping (hulls) and aerospace industries (aircraft bodies), power lines, and food packaging (cans and other containers, foil). Aluminum salts and compounds are used for water purification, in which alum (KAl(SO4)2.12H2O) is important, as catalysts in the chemical industry, and as ingredients in cosmetics (antiperspirants), pharmaceuticals (antacids, vaccine adjuvant), and foods (baking powder, spreading agent) (Table 1).
Application of response surface methodology (RSM) for optimizing coagulation process of paper recycling wastewater using Ocimum basilicum
Published in Environmental Technology, 2020
Mohammad Reza Mosaddeghi, Farshid Pajoum Shariati, Seyed Ali Vaziri Yazdi, Gholamreza Nabi Bidhendi
The effect of parameters and their combinations can be optimized by using RSM. According to obtained results, optimal variables of pH 8.3, the alum: O. basilicum ratio of 2.82, and contact time of 48.85 min led to 85% colour reduction and 82% TSS removal. The actual experimental values deviate from the predicted data by 2.35% in colour reduction and by 0.9% in TSS removal. The optimum condition led to rapid adsorption and inter-particle bridging. In addition, the rate of turbidity and COD reduction at the optimal conditions was evaluated, and the results showed turbidity reduction of 78%, COD reduction of 40%, and BOD5 removal of 60%. Also, treated wastewater had the BOD5/COD ratio of 0.44 at the optimum conditions, indicating biodegradability of the treated wastewater [53]. Under these conditions, the use of alum can be reduced by using natural coagulants like basil mucilage, which may result in lowering costs and overcoming environmental issues because the use of alum alone in optimum condition requires higher amounts of alum.