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Removal of congo red from wastewater by adsorption onto waste red mud
Vol 34 No 2, pp 401417, 1997 Copyright 1997 Elsevier Science Ltd Printed in Great Britain All rights reserved 0045.6535/97 $17.00+0.00 Chemosphere, PII: SOO45-6535(96)00385-Z REMOVAL OF CONGO RED FROM WASTEWATER BY ADSORPTION ONTO WASTE RED MUD C NAMASIVAYAM* and D J S E ARASI Environmental Chemistry Division Department of Environmental Sciences Bharathiar University Coimbatore - 641 046 Tamil Nadu - INDIA (Received in USA 23 June 1996; accepted 23 August 1996) ABSTRACT Waste generated for during the red the adsorption Adsorption as dye concentration, data The isotherms dye was quantitative suggest that exchange.0 Key words first mg/g the Elsevier : Waste red the solution parameters agitation time Author E-mail: to whom and pH equilibrium both Langmuir and Freundlich capacity of was the found of pH and of Science congo red, All to mud be desorption adsorption Ltd red is rights adsorption correspondence should sandflas250.bharathi.ernet.in 401 for the nearly studies mostly ion reserved isotherms pH effect * such The Effect mud, is recycled expression mechanism 1997 dose, ore, aqueous using Adsorption 2.0 from byproduct, rate obeyed at pH red studied adsorption 4.05 of bauxite adsorbent followed adsorption congo were industrial an processing of kinetics Adsorption mud, be addressed 402 INTRODUCTION Colour is one of the characteristics of an effluent which is easily detected and readily traced back to its source Most dyes are stable to biological degradation Coloured waters are often objectionable on aesthetic grounds for drinking and other agricultural purposes Colour affects the nature of the water by inhibiting sunlight penetration thus reducing carcinogenic photosynthetic and mutagenic action Some (1) Hence there dyes are is a need to remove dyes from wastewaters before it mixing with receiving waters The treatment of dyes in industrial wastewaters poses several problems photodegradation treated by the Activated available adsorbent is carbon and has of aerobic an attractive adsorbent stable to (2); hence, they cannot be methods of dyes provides if popular and oxidation conventional Adsorption removal since dyes are generally been alternative inexpensive the most used with is digestion readily and efficient great for and success However, high costs in the procurement of activated carbon restricts its Namasivayam adsorbents These (3) in has developing recently, countries reviewed like India non-conventional used for the removal of dyes and heavy metals include residual use slurry agricultural (4), banana solid pith wastes such (5), orange as biogas peel (6), 403 bagasse as and paddy straw Fe(III)/Cr(III) Namasivayam of dairy (11) and coworkers from employed solutions of using containing congo fly ash and coal(g) et al (12) have of nickel of this a textile such of chlorophenol study was to evaluate red mud for the treatment red, waste red mud for the treatment Zouboulis for the removal The objective feasibility and solid (10) and for the removal aqueous red mud industrial hydroxide(8) wastewater employed (7) and the of wastewater dye as a typical case (13) EXPERIMENTAL Materials Waste Aluminium the at Factory adsorbent water for red Tamil Nadu, powder was was obtained from M/S India) was washed particulate fine The obtained thoroughly was very h Congo studies mud (Mettur, It to remove 60°C red used used CIBA for as distilled ( < 53 /A) and then from with Mettur dried adsorption - GEIGY (Bombay, India) Methods Batch by agitating 250 mg of adsorption 50 mL of dye adsorbent temperature (30 solution separated at 8,600 was x g ? in The 2'C) solution glass using from dye experiments the at natural bottles a at shaker adsorbent removal were was 140 carried pH (7.3) with rpm machine out at The room dye by centrifugation estimated spectro- 404 photometrically wavelength by monitoring of maximum spectrophotometer For removal, the (Model U-3210, studies on initial of the with dye pH (495.8 the Hence the from absorbance adjusting final pH to 7.3 adsorption experiments evaluating follows: time After supernatant adsorbent samples dye varied from no change the of the of dye solutions data were for effect dye after Langmuir taken from and batch of agitation dose in absorbance removal and adsorbent desorption adsorption of 10 mg/L greater Several was upon time, on per cent respectively Batch solution cent The isotherms dye concentration at the a Hitachi pH was conditions values adsorption removal, of solution per Freundlich initial effect in acidic was determined and nm) using 7.3 to 11.0 there But changes Tokyo) pH of the dye changed the absorbance absorption to 11 In the pH range absorbance the than dye was such were different separated as before pH and the samples values experiments equilibrium was gently were agitated were time remove prepared with for from the adsorbent 50 100 mL 50 i.e The any Then of The out mL of as dye for an agitation discarded to carried with 250 mg of adsorbent solution washed studies 100 min, dye loaded unadsorbed the spent water by centrifugation dye adsorbent adjusted desorbed the dye to was and estimated 405 RJZ!3ULTSANDDISCUSSION Effect of contact time and concentration Figure initial The concentration removal contact until of time was rapid gradually concentrations 36.5 10 to $ to 40 mg/L continuous surface used agitation of congo in the decreased The time was The equilibrium 25.7 % as dye removal indicating time and red by red mud initial with stages lapse of of time 90 uptake for all the dye of dye decreased concentrations curves monolayer increased from were single, smooth coverage of on dye and outer of adsorbent 20 40 60 80 loo Agdatlon Fig of equilibrium The equilibrium from effect on adsorption dye and shows 120 lime 140 160 180 200 (min) Effect of agitation time and dye concentration on removal: Dye concentration:(O)10 mg/L,(D) - 20 mg/L,(A)30 mg/L,(e)40 mg/L, Adsorbent dose - 250 mg/50 mL; pH - 7.3 406 Adsorption dynamics The by red mud was log10 where qe and equilibrium the rate (qe - Pig using q are the at time vs qe amounts t (sin), were which Lagergreen adsorption order plots rate rate equation of dye adsorbed Linear that expression (4), for dye adsorption at is of loglo different dye adsorption (Fig (mg/g) and kad plots for the red (1) respectively, obtained indicate of congo kadt _ 2.303 of adsorption t the first for Lagergren (qe - 9) = log10 constant 9) constant studied and concentrations, follows rate process 2) Adsorption 407 rate constants rate (kad) are presented constants slurry for (4) waste banana Fe(III)/Cr(III) 0.106, 0.0406 congo red pith hydroxide and 0.34 in Table (50 mg/L) (5), orange (8) l/min, were Adsorption on biogas peel waste (6) and waste reported to be 0.028, respectively Table - Rate constants for adsorption Concentration of congo red (mg/L) Langmuir 10 3.34 x 1o-2 20 6.66 x 1o-2 30 7.55 x 1o-2 40 3.57 x 1o-2 isotherm Langmuir adsorption on a isotherm surface identical sites adsorption on the surface in the Adsorption rate constant k ad (I/min) plane represented of The the containing model assumes valid a surface The for finite uniform and no transmigration by the equation ‘e -=-+ is Langmuir monolayer number of energies of of adsorbate isotherm (6) 'e (2) is 408 where, The C e is the concentration constant related 'e Q, signifies to the energy shows that the The values slope and intercept Table The applicability and of the coverage of and b values non-conventional of Q, congo red 10 Langmuir plot isotherm the are shown 15 20 25 surface of congo in Table 30 hg/L) for dye adsorption is of C,/q, vs Langmuir and isotherm from and are presented adsorption Ce Fig on plot b calculated plot of Langmuir adsorbents b were at equilibrium capacity Linear follows linear for the 1: (mg/L) adsorption adsorption 3) The Q, the of adsorption (Fig monolayer of dye 35 suggests of red red the in the mud by some 409 Table Langmuir - constants Q Adsorbent Ref L/w4 44.00 0.0505 Waste Fe(III)/Cr(III) Waste Orange peel 22.44 0.0680 Waste banana pith 20.29 0.0900 9.50 0.2116 Biogas waste hydroxide b w9g slurry Waste red mud 4.05 0.0360 Paddy straw 1.01 0.8700 The isotherm called can characteristics essential expressed be equilibrium by parameter, a of dimensionless RL, which This work Langmuir constant, is defined by, l SC + bco where b is the concentration and Langmuir red mud and The RL values (mg/L) 1, indicating constant favourable found for initial dye to be between congo red on studied(6) isotherm Freundlich adsorption were is the adsorption for all the concentrations Freundlich Co of congo equation red on red mud was also (5) applied for the 410 X log10 - = log10 kf + - m where of x is the the amount adsorbent of dye used (g), is Ce in solution (mg/L) incorporating all affecting as follows kf adsorption x/m log10 capacity vs log10 Freundlich 'e isotherm greater value, values factors will of k, and n are be shown and the equilibrium and kf and the constants adsorption process, intensity Linear that (Fig 4) In general, the plot adsorption adsorption in Table capacity along with non-conventional adsorbents 05 reported those in literature Corr coetft=0.9904 o-4 03- o-0 \ - -3 I -0 02 I 0.4 I 06 08 10 12 kl;c,Ce Fig Freundlich plot for dye adsorption 14 i6 of also higher L other dye n are shows the (4) ce (mg), m is the weight adsorbed concentration such log10 n the The of 411 Table - Freundlich constants Adsorbent Paddy straw Waste Fe(III)/Cr(III) Waste banana Biogas waste 7.69 2.01 1.93 pith 1.20 1.46 slurry I.20 1.50 1.21 1.82 14 hydroxide red mud Effect 0.22 increased than from (Fig the initial to 5) initial 11 the The per pH cent decrease on the base is important removal vs of aqua dissociation of per cent pH the after initial This work final pH with complex solution was removal decreased from adsorption the per increase was cent shown and removal in Fig (13) The 5c The explained subsequent interface is (13); hence, in pH may be formation higher to This of red mud is also at solid/solution dye pH range of alkalinity to explain in adsorption basis pH final pH in the due to the contribution final 1.46 of pH When 98 to Ref 4.79 Wollestonite Waste n k, acid- 412 I L I I I I ,& , 10 II Final pH 13 100 80 11 1: , "P O9++rk 10 Initial 12 14 16 pH Fig A Effect of initial pH on per cent removal of dye B Effect of initial pH on Final pH C Per cent removal vs Final pH In acid medium, positive charge develops on the surface of oxides of adsorbent and may be written as H+ M-O / + H-OH > "\ M - OHZ+ / + OH- (5) 413 where the M stands solution surface with of Cl- for Al or Si present is acidified positively ions The by hydrochloric charged chloride in the interface ions are red mud Since the outer acid, will be associated exchanged with dye anions M - OHa+ / Cl- + "\ M - OH2+ Dye- > 0/ / Dye- + Cl- O/ (6) With an oxide/solution charged in interface of the adsorbent negatively increase i.e charged pH, decreases positive charge At pHs above - 10, the adsorbent and will ions of the solution be on the pH-zpc surface associated with in the following the becomes positively manner: (7) Thus surface outer consequently observed and there of the are the waste Fe(III)/Cr(III) exchangeable adsorbent adsorption in the adsorption no at decreases of congo anions higher Similar the pHs and trend was red on wollastonite hydroxide(8) on (14) 414 Desorption studies Desorption mechanism This of adsorption may make desorption medium mechanism and increases with in the 3I process 4I stated 5I in the studies I I I Effect of pH on per cent adsorbent The per cent pH of the again aqueous confirms in the pH effect the to the pH effect I PH Fig and economical increase desorption elucidating of dyes is just opposite of adsorption 01 help recovery the treatment (Fig 6) This observation studies desorption I 10 I 11 The the 415 CONCLUSIONS Red mud, a waste industry, can the removal The be The from effectively of congo adsorption isotherms byproduct, a bauxite used as an processing adsorbent for red from wastewaters followed both Langmuir Langmuir adsorption and Freundlich capacity was 4.05 m9/9 Almost quantitative dye removal occurred at the initial pH of 2.0 The kinetic technologist data may in designing removal from wastewaters As adsorbent the processing be useful treatment enriched i.5 discarded the industry, for plants with as treatment environmental congo waste method for colour red in is bauxite expected to be economical ACKNOWLEDGEMENT Authors authorities facilities for are thankful providing to Central Bharathiar University Instrumentation Lab 416 REFERENCES McKay, G., Fuller's stuffs Otterburn, earth and K S and using and and clay Jamal, as Rate Aga, adsorbents constants J for A dye Water, Air, of cationic dyes 24 : 307 - 3.22 (1985) Lee, coconut S fired Equilibrium Soil pollution, Low, M C K husk as The an removal adsorbent Pertanika, 13, treatment of 221 - 228 (1990) Namasivayam, C wastewaters, Pollution Adsorbents In and Enviro-Media, : the Encyclopedia Control, Karad, for Vol Environmental of 1, Ed.: Maharastra, Trivedy, India, 1995 R K pp 30 - 49 Namasivayam, from Chem Technol Namasivayam, and C and Technol., by by solutions K of waste congo slurry red J 53 : 153 - 157 (1992) N Removal waste : 32 - 42 N Removal celluosic Removal biogas by Technol Muniasamy, (1996) T Kanchana, J Sci C., R Bio Technol, Ranganathan, solutions Yamuna, solutions aqueous Pertanika and aqueous Namasivayam, from C waste Gayathri, of dyes orange of congo red pith banana (1993) K., Rani, M from aqueous peel Biores 417 Deo, N and Ali, : Congo material 13 : 496 - Namasivayam, C., from Fe(III)/ Cr(II1) G red Adsorption a new low J Environ cost Prot R wastewater and by hydroxide Yamuna, R adsorption Waste T on Dye waste Management, : 14 (1994) S., Prasad, G and chrome dye from aqueous : ash fly by : Indian - Jeyakumar, removal Gupta, Dye (1993) 508 643 - 648 M and Singh, solutions coal.Water V N Removal by mixed Research, of adsorbents : 24 45 - 50 (1990) 10 Namasivayam, waste C water and Ranganathan, using red mud Treatment K Res Ind 37 of dairy : 165 - 167 (1992) 11 Namasivayam, C and chlorophenol Environ 12 Zouboulis, toxic A 13 HO, G mud 43rd Singh, congo V Kydros, The Bio Technol, application N., 58 the mud, K A case 95 for G red 101 (1993) Waste and of nickel and Conf., and 2J mud J sodicity rehabilitation M I., (1989) Mishra, - Use of salinity red by wollastonite, - 71 (1984) : Industrial Chelsea, Lewis, 14 Communicated removal, of International (1995) I and Purdue Adsorption red E Overcoming and K waste Studies metals Technol by Thamaraiselvi, for Chem of red reuse, Proceedings pp 641 - 649 Panday, Indian K K Removal J Technol of 22 : 70 ... Namasivayam, and C and Technol., by by solutions K of waste congo slurry red J 53 : 153 - 157 (1992) N Removal waste : 32 - 42 N Removal celluosic Removal biogas by Technol Muniasamy, (1996) T... The Q, the of adsorption (Fig monolayer of dye 35 suggests of red red the in the mud by some 409 Table Langmuir - constants Q Adsorbent Ref L/w4 44.00 0.0505 Waste Fe(III)/Cr(III) Waste Orange... removal The be The from effectively of congo adsorption isotherms byproduct, a bauxite used as an processing adsorbent for red from wastewaters followed both Langmuir Langmuir adsorption and Freundlich