Suitability of aluminum material on sugar industry wastewater with chemical and electrochemical treatment processes

International Journal of Industrial Chemistry (2019) 10:335–347 https://doi.org/10.1007/s40090-019-00196-8 RESEARCH Suitability of aluminum material on sugar industry wastewater with chemical and electrochemical treatment processes Omprakash Sahu1 Received: 28 April 2018 / Accepted: 11 November 2019 / Published online: 20 November 2019 © The Author(s) 2019 Abstract Aluminum is a valuable material, which can be used for water and wastewater treatment. It exists in metal as well as in salt form. The efficiency of water and wastewater treatment depends upon the technology applied to treat. Sugarcane industry is coming under those industries which have a large amount of freshwater and release large amount of effluent. The goal of this research work is to study the behavior of aluminum metal and salt for the treatment of sugar industry wastewater on chemical oxidation and electrochemical oxidation. The effect of pH, dosing, temperature and catalysis on metal and salt has been also studied with both treatment methods. The results show that maximum 90% of chemical oxygen demand and 94% of color removal can be achieved with an aluminum electrode (electrocoagulation) at optimum conditions, pH 7, current density 178 A/m2, electrode distance 20 mm, and salt solution 0.5 M NaCl. In the same way, 81% chemical oxygen demand and 85% color removal were achieved with alum for the 0.5 M lime solution, at 50 mM mass loading, 21 °C operating temperature and optimum pH of 7, respectively. The sludge generated after treatment was also analyzed with settling filtration, thermal, FTIR and SEM. Keywords Anode material · Chemical oxygen demand · Effluent · Optimization · Sludge Introduction Aluminum is the most abundant metal and the third most abundant element in the earth’s crust, after oxygen and silicon. It makes up about 8% by weight of the earth’s solid surface and it never occurs as a free element in nature [55]. It is a light, conductive, corrosion-resistant metal with a strong affinity for oxygen. This combination of properties has made it a widely used material, with applications in the aerospace, architectural construction and marine industries, as well as in wastewater treatment [11]. The aluminum salts with chloride, nitrate and sulfate are highly soluble and form a range of dissolved species on contact with water. The fate and behavior of aluminum in the aquatic environment are very complex [15]. Aluminum speciation, which refers to the partitioning of aluminum among different physical and chemical forms, and aluminum solubility are affected by a wide variety of environmental parameters, including pH, * Omprakash Sahu 1 Department of Chemical and Petroleum Engineering, UIE, Chandigarh University, Gharuan, Mohali, India solution temperature, and dissolved organic carbon (DOC) content. Metals in solution may be present as dissolved complexes, as “free” or aquo ions, in association with particles, as colloids or as solids in the process of precipitation [19]. In wastewater treatment, it can be used as an electrode in the electrocoagulation method, chemical salt as coagulant and sludge as red mud [56]. Aluminum salts are widely used as coagulants in water treatment process due to the effectiveness in removing a broad range of impurities, including colloidal particles and dissolved organic substances [54, 60]. The mode of action is generally explained in terms of two distinct mechanisms: charge neutralization of colloids by cationic hydrolysis products and incorporation of impurities in an amorphous hydroxide precipitate. The relative importance of these mechanisms depends on factors such as pH and dosage [48]. Alternative coagulants, based on pre-hydrolysed forms of aluminum are more effective than the traditional additives in many cases, but their mode of action is not completely understood, especially with regard to the role of charge neutralization and hydroxide precipitation. Electrocoagulation is another way to treat the water and wastewater in which aluminum is used as an electrode [32]. In the EC process, coagulation is generated in situ 13 Vol.:(0123456789) 336 International Journal of Industrial Chemistry (2019) 10:335–347 by electrolytic oxidation of an appropriate anode material [42]. During this process, charged ionic species are removed from wastewater by allowing it to react with an ion having opposite charge, or with flock metallic hydroxides generated within the effluent [16, 21]. Aluminum in form plate has been used to treat the textile industry wastewater [12], dye wastewater [30], heavy metal [23], sewage water [42], petrochemical wastewater [31], dairy wastewater [13], hospital wastewater [20], etc. and in form of salt for leachate [52], dairy wastewater [36], pesticide wastewater [57], and tannery wastewater [43]. Aluminum is easily available, economically fit and highly efficient as compared to other metals for industrial effluent and drinking water treatment [41]. Sugar industry is one major high amount water consumer and discharges large quantity of wastewater [38]. Hence, with this information, an experimental was conducted to treat the sugar industry effluent with aluminum salt and electrode. The main aim of this research work is to evaluate the performance and effectiveness of aluminum (salt and electrodes) to treat the sugar industry wastewater by the chemical and electro-oxidation techniques. The experimental operating parameters, effect of initial pH, current density applied, and distance between electrodes were scrutinized for sugar industry wastewater. Materials and methods Materials The wastewater used for the experiments was arranged from Bhoramdev Sugar Industry Ltd., Kavardha (C.G.), India. The composition of effluent before and after treatment is reported in Table 1. Analytical grade chemicals from Merck Limited, Mumbai, India, were used for analysis. The aluminum sheet was used as electrode and it was arranged from the local market. Experimental methods The complete setup of an experiment program is shown in Fig. 1. The batch electrocoagulation cell used in the experimental study was constructed of plexiglass and the configuration is given in Table 2. The electrode arrangement consisting of four aluminum plates was used to connect the parallel electrodes in a monopolar mode (anodes and cathodes are in parallel connection, the current is divided between all the electrodes in relation to the resistance of the individual cells). The electrodes were connected to a DC power supply. Suspensions were stirred using a magnetic stirrer adjusted to an optimal rate (300 rpm) to attain the highest efficiency of turbidity removal. A digital thermometer (range 140 °C) was employed to measure the temperature of the suspensions, respectively. The current that flows through the cell and the voltage across the electrodes were measured with an ammeter and a voltmeter, respectively. Before each electrocoagulation run, the electrodes were washed with 1 (...truncated)