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Adsorpcija metilenske plavosti iz tekstilnih otpadnih voda sa pirolizovanom ljuskom oraha
Adsorption of methylene blue from textile wastewater with pyrolyzed walnut shell
Sažetak
Ispuštanje obojene otpadne vode, posebno tekstilnih aplikacija, u prijemno okruženje može izazvati ozbiljne probleme životne sredine. Konvencionalne metode nisu poželjne jer nisu uspešne u tretmanu obojenih otpadnih voda ili nisu ekonomične. Među različitim tehnikama, adsorpcija dobija na značaju u uklanjanju zagađivača iz otpadnih voda zbog niskih operativnih troškova i lakoće upotrebe. Interesantna je upotreba poljoprivrednog otpada kao jeftinih adsorbenata u uklanjanju boja iz otpadnih voda nakon primene različitih procesa aktivacije. Cilj ovog istraživanja je da se proceni sposobnost adsorpcije boje metilen plavo (MB), koja se koristi u tekstilu, iz vodenih rastvora sa ljuskom oraha (VAC), poljoprivrednog otpada koji je pirolizovan i aktiviran fosfornom kiselinom. U studiji su serijski eksperimenti izvođeni pri fiksnoj dozi adsorbenta (0,1 g/200 mL), konstantnoj temperaturi (20 0 C), različitim pH vrednostima (4, 6, 7, 9, 11), različitim kontaktnim vremenima (0, 5, 15, 30, 60, 90 i 120 minuta), različite početne količine boje (2, 4, 6, 8 i 10 mg/L) i različite doze adsorbenta (0,05, 0,1, 0,2, 0,5 i 1 g / 200 mL). Štaviše; Efekat jonske snage na efikasnost uklanjanja boje iz rastvora boje je procenjen dodavanjem različitih doza soli (500, 1000, 1500, 2000 i 2500 mg/L NaCl). Povećanjem pH vrednosti rastvora boje sa 4 na 11, efikasnost uklanjanja boje pomoću VAC-a je određena kao 65% na 90 minuta za pH:9, 4 mg/L MB koncentracije i 0,1 g/200 mL doze adsorbenta. Optimalne pH vrednosti su određene kao 9 za VAC. U svim eksperimentima, adsorpcija se povećava sa povećanjem vremena kontakta, a efikasnost uklanjanja opada sa povećanjem koncentracije boje. Efikasnost uklanjanja boje blago se povećala sa povećanjem jonske snage. Dok je efikasnost uklanjanja od 38% postignuta primenom 2000 mg/L NaCl za 90 minuta, efikasnost uklanjanja je smanjena na 30% sa primenom 2500 mg/L NaCl.
Abstract
Discharge of colored wastewater, especially textile applications, into receiving environments can cause serious environmental problems. Conventional methods are not preferred because they are not successful in the treatment of colored wastewater or are not economical. Among different techniques, adsorption is gaining importance in pollutant removal from wastewater due to its low operating cost and ease of use. The use of agricultural wastes as low-cost adsorbents in the removal of dyestuffs from wastewater after applying various activation processes is of interest. The aim of this study is to evaluate the adsorption performance of methylene blue (MB) dye, which is used in textile, from aqueous solutions with walnut shell (WAC), an agricultural waste that has been pyrolyzed and activated with phosphoric acid. In the study, in batch experiments were carried out at fixed adsorbent dose (0.1 g/200 mL), constant temperature (20 0 C), different pH values (4, 6, 7, 9, 11), different contact times (0, 5, 15, 30, 60, 90 and 120 minutes), different initial dyestuff amounts (2, 4, 6, 8 and 10 mg/L) and at different adsorbent doses (0.05, 0.1, 0.2, 0.5 and 1 g/ 200 mL) was carried out. Moreover; the effect of ionic strength on the color removal efficiency from the dye solution was evaluated by adding different salt doses (500, 1000, 1500, 2000 and 2500 mg/L NaCl). By increasing the pH value of the dye solution from 4 to 11, the color removal efficiency by WAC was determined as 65% at 90 minutes for pH:9, 4 mg/L MB concentration and 0.1 g/200 mL adsorbent dose. Optimum pH values were determined as 9 for WAC. In all experiments, adsorption increased with increasing contact time, and removal efficiency decreased with the increase in dye concentration. The color removal efficiency increased slightly with increasing ionic strength. While 38% removal efficiency was achieved with 2000 mg/L NaCl application in 90 minutes, the removal efficiency decreased to 30% with 2500 mg/L NaCl application.
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