Direct Blue 71 Removal from Aqueous Solutions by Adsorption on Pistachio Hull Waste: Equilibrium, Kinetic and Thermodynamic Studies

Abstract

Background and Purpose: Azo dyes including Direct Blue 71 (DB71) are toxic, mutagenic and carcinogenic contaminants in effluents of industries. This study aimed to investigate the adsorption of DB71 from aqueous solution onto pistachio hull waste (PHW) as a low-cost adsorbent. Materials and Methods:A series of experiments were performed via batch adsorption technique to examine the effect of the process variables such as contact time 0-210 minutes, initial dye concentration 10-100 mg/l, pH 2-12, adsorbent 0.05-1 g/l, and the processing temperature of 25, 40, and 50° C. The concentration changes of DB71 were measured using the colorimetric method by the spectrophotometer T80 ultraviolet/visible at the 587 nm wavelength. Moreover, The PHW was characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, Freundlich and Langmuir isotherm model, pHpzc and Brunauer-Emmett-Teller (BET) surface area analysis.Results: Maximum adsorption capacity was 90.48 mg DB71 per 1 g adsorbent at pH 2, DB71 100 mg/l, temperature 50° C, and time 210 minutes. In general, by increasing the adsorbent dosage, time, and processing temperature, the removal efficiency was increased; however, incrementing pH and dye concentration had a reverse effect. Maximum BET specific surface and total pore volume on the adsorbent were 1.04 m 2 /g and 0.0002 cm 3 /g, respectively. The Freundlich isotherm (R 2 = 0.9912) model fits the equilibrium data better than the Langmuir isotherm (R 2 = 0.9024) model. The adsorption kinetic was found to be well described by the pseudo-second-order model. Thermodynamic analysis indicated that the adsorption process is a spontaneous and endothermic process. Conclusion:PHW can be used well as a low-cost surface adsorbent in the treatment of DB71 from aquatic environments.

Investigation of Fluoride Adsorption from Aaqueous Solutions by Modified Eucalyptus Leaves: Isotherm and Kinetic and Thermodynamic Studies

“…Additionally, investigating the initial concentration of fluoride on the adsorption process showed that as the concentration of fluoride increased, the removal efficiency decreased, in a way that the highest efficiency (90%) was achieved at a concentration of 5 mg/L. The reason for this was the saturation of available adsorption spaces and their ineffectiveness at higher concentrations (30,31). The results obtained at this stage were found to be consistent with the findings of certain other studies (12,28).…”

Removal of diazo-dye Direct Blue 2 (DB2) in aqueus solution by P(HEMA) nanoparticles

“…Son yıllarda yapılan çalışmalarda buğday kabuğu [58], çok duvarlı karbon nanotüp [59], Carica papaya yaprağı [60], fıstık kabuğu atığı [61] ve modifiye zeolit [62] gibi farklı adsorbentlerin kullanılabilirliği rapor edilmiştir. Biyo-uyumlu ve ekonomik olan bu tür adsorbentlerin kullanılan adsorbent miktarının fazla olması [58] ve uzun adsorpsiyon süresi [58,61], adsorpiyon kapasitesinin düşük olması [59,60,62]…”

“…Özellikle maliyetinin düşük olması, kolay hazırlanıyor olması ve uygulanan işlemin basit olması nedeniyle Direct Blue türü azo boyaların atık sulardan gideriminde adsorpsiyon yöntemi sıklıkla kullanılmaktadır [54,55,56,57,58]. Son yıllarda yapılan çalışmalarda buğday kabuğu [58], çok duvarlı karbon nanotüp [59], Carica papaya yaprağı [60], fıstık kabuğu atığı [61] ve modifiye zeolit [62] gibi farklı adsorbentlerin kullanılabilirliği rapor edilmiştir. Biyo-uyumlu ve ekonomik olan bu tür adsorbentlerin kullanılan adsorbent miktarının fazla olması [58] ve uzun adsorpsiyon süresi [58,61], adsorpiyon kapasitesinin düşük olması [59,60,62] ve desorpsiyon ajanı olarak aseton gibi organik ürünlerin kullanılması [63] gibi bazı dezavantajları mevcuttur.…”

Operational parameters affecting the removal and recycling of direct blue industrial dye from wastewater using bleached oil mill waste as alternative adsorbent material

“…Overall, effluent treatments aiming to reduce the amount of dyes having a structure similar to DB, are known in literature, as for example degradation methods through Fenton's oxidation process. [2] The Direct Blue 78 photocatalytic degradation using TiO2 nanoparticles immobilized on recycled wool-based nonwoven material, was presented by Markovic et al [16] The DB 71 adsorption from aqueous solution onto pistachio hull waste as a low-cost adsorbent was also presented by Biglari et al [17] Activated carbon and poly pyrrole polymer composite prepared from Thevetia Peruviana were presented as materials to adsorb DB 71. [18] Without doubt the list is not complete for describing the plethora of studies in literature about the azoic blue dye removal or its degradation in aqueous environment, however in the present paper we highlight the use of a handy material exhibiting very high capabilities in sequestering the direct dye within few minutes in appropriate conditions.…”