Doğal adsorban olarak tüf (Doğantarla-Aksaray) ile sulardan ağır metal gideriminin incelenmesi
Yükleniyor...
Dosyalar
Tarih
2014
Yazarlar
Dergi Başlığı
Dergi ISSN
Cilt Başlığı
Yayıncı
Aksaray Üniversitesi Fen Bilimleri Enstitüsü
Erişim Hakkı
info:eu-repo/semantics/openAccess
Özet
Bu çalışmada, doğal süreçler ve endüstriyel faaliyetler sonucu çevreye ulaşabilen ve biyolojik olarak bozunmaya uğramaması sebebiyle birikim yoluyla ekosistem ve insan sağlığı üzerinde zararlı etkileri olan ağır metallerin sucul ortamlardan giderim yöntemlerinden biri olan adsorbsiyon metodu ile giderimi incelenmiştir. Çalışmamızda dikkat çeken en önemli nokta; Aksaray ili Doğantarla bölgesinden toplanan tüfün böyle bir amaç için ilk kez doğal adsorban olarak kullanılmasıdır. Sulardan ağır metal giderim yöntemlerinden; kimyasal çöktürme, iyon değiştirme, membran teknolojileri, koagülasyon- flokülasyon, flotasyon ve elektrolizin yanında adsorpsiyon çok düşük konsantrasyonlarda uygulanabilirliği, kesikli ve sürekli proseslerde kullanılabilirliği, operasyon kolaylığı, az miktarda atık çamur üretimi, yenileme ve yeniden kullanım olanağına ve düşük sermaye maliyeti avantajlarına sahiptir. Doğal adsorban olan Doğantarla Tüf'ünün adsorpsiyon özelliklerini belirlemek amacıyla 5 farklı metal (Cd2+, Cu2+, Ni2+, Pb2+ ve Zn2+ ) için kinetik ve izoterm çalışmalarının yanında adsorpsiyon işlemine etki eden parametlerde (temas süresi, sıcaklık, pH, adsorban miktarı ve adsorban tane boyutu) incelenmiştir. Cd2+, Cu2+, Ni2+, Pb2+ ve Zn2+ için en uygun izoterm modeli Redlich-Peterson ve en uygun kinetik modeli yalancı ikinci derece olarak belirlenmiştir. Redlich-Peterson izoterminin ? değeri, 1'e yaklaştığından Langmuir izoterm modeline uyum göstermiştir. Langmuir izoterminde elde edilen maksimum adsorpsiyon kapasiteleri (Qmax); Ni2+>Pb2+>Zn2+> Cd2+> Cu2+ iyonları için sırasına göre 18.31, 16.00, 13.77, 12.00 ve 8.12 (mg g-1) olduğu bulunmuştur. Yalancı ikinci derece kinetik modeli Cd2+, Cu2+, Ni2+, Pb2+ ve Zn2+ iyonları için sırası ile hız sabiti (k2) değerleri 0.0028, 0.0661, 0.0503, 0.0498 ve 0.0469 g/mg.dk olarak belirlenmiştir. Termodinamik çalışmalar neticesinde Cd2+, Cu2+, Ni2+, Pb2+ ve Zn2+ iyonları için sırasıyla ?G? değeri -0.98, -2.85, -7.36, -7.23 ve -4.01 kJ/mol ve ?H? değerleri ise 27.14, 27.14, 4.73, 6.89 ve 35.69 kJ/mol olarak bulunmuştur. ?G? ve ?H? değerlerine göre Doğantarla tüfü üzerindeki adsorpsiyonun fiziksel adsorpsiyon olarak oluştuğu belirlenmiştir.
The industrialization process cause to many heavy metal ions have been discharged into the environment as waste, which causes soil pollution and water pollution. The presence of heavy metal ions in water, even at very low levels, can cause damages to ecosystem and human life, because they are not biodegradable. With this reason, adsorption process for the removal of heavy metals was investigated in this study. The most noteworthy point of this study: tuff collected from the Doğantarla region, is used as a natural adsorban for such a purpose at the first time. Methods used to remove heavy metals from wastewater include reduction and precipitation, coagulation and flotation, adsorption, ion exchange, membrane technology, and electrolysis. Adsorption has the additional advantages of applicability at very low concentrations, suitability for using batch and continuous processes, ease of operation, little sludge generation, possibility of regeneration and reuse, and low capital cost. The adsorption behaviour of Doğantarla tuff has been studied in order to determine its removal efficiency of heavy metals solutions that containing Cu2+, Pb2+, Cd2+, Ni2+ and Zn2+ respectively. Tests to determine both the rate of adsorption and the uptake at equilibrium were performed under batch conditions from single component solutions. The effect of pH, temperature, agitation time, size of adsorban and amount of adsorban on the extent of adsorption was investigated. The Redlich-Peterson isotherm and pseudo-second-order model best fitted the adsorption data of Cd2+, Cu2+, Ni2+, Pb2+ and Zn2+. The maximum adsorption capacities (Qmax) of Doğantarla tuff as obtained from Langmuir adsorption isotherm were found to be 8.12, 12.00, 13.77, 16.00 and 18.31 (mg g?1) for the adsorption of metal ions in order of Ni2+ > Pb2+ > Zn2+ > Cd2+ > Cu2+. The experimental results demonstrate that the above selective order of adsorption capacity is due to formation of stable chelating ring between the natural Doğantarla tuff and metal ions. The rate constant of pseudo-second-order model were found to be 0.0028, 0.0661, 0.0503, 0.0498 ve 0.0469 g mg-1.min-1, respectively. ?G? and ?H? values were found to be -0.98, -2.85, -7.36, -7.23 and -4.01 kJ mole-1, and 27.14, 27.14, 4.73, 6.89 and 35.69 kJ mole-1, respectively. According to these values, the adsorption formed on the Dogantarla tuff was determined by physical adsorption.
The industrialization process cause to many heavy metal ions have been discharged into the environment as waste, which causes soil pollution and water pollution. The presence of heavy metal ions in water, even at very low levels, can cause damages to ecosystem and human life, because they are not biodegradable. With this reason, adsorption process for the removal of heavy metals was investigated in this study. The most noteworthy point of this study: tuff collected from the Doğantarla region, is used as a natural adsorban for such a purpose at the first time. Methods used to remove heavy metals from wastewater include reduction and precipitation, coagulation and flotation, adsorption, ion exchange, membrane technology, and electrolysis. Adsorption has the additional advantages of applicability at very low concentrations, suitability for using batch and continuous processes, ease of operation, little sludge generation, possibility of regeneration and reuse, and low capital cost. The adsorption behaviour of Doğantarla tuff has been studied in order to determine its removal efficiency of heavy metals solutions that containing Cu2+, Pb2+, Cd2+, Ni2+ and Zn2+ respectively. Tests to determine both the rate of adsorption and the uptake at equilibrium were performed under batch conditions from single component solutions. The effect of pH, temperature, agitation time, size of adsorban and amount of adsorban on the extent of adsorption was investigated. The Redlich-Peterson isotherm and pseudo-second-order model best fitted the adsorption data of Cd2+, Cu2+, Ni2+, Pb2+ and Zn2+. The maximum adsorption capacities (Qmax) of Doğantarla tuff as obtained from Langmuir adsorption isotherm were found to be 8.12, 12.00, 13.77, 16.00 and 18.31 (mg g?1) for the adsorption of metal ions in order of Ni2+ > Pb2+ > Zn2+ > Cd2+ > Cu2+. The experimental results demonstrate that the above selective order of adsorption capacity is due to formation of stable chelating ring between the natural Doğantarla tuff and metal ions. The rate constant of pseudo-second-order model were found to be 0.0028, 0.0661, 0.0503, 0.0498 ve 0.0469 g mg-1.min-1, respectively. ?G? and ?H? values were found to be -0.98, -2.85, -7.36, -7.23 and -4.01 kJ mole-1, and 27.14, 27.14, 4.73, 6.89 and 35.69 kJ mole-1, respectively. According to these values, the adsorption formed on the Dogantarla tuff was determined by physical adsorption.
Açıklama
Anahtar Kelimeler
Adsorpsiyon, Doğal Materyal, Tüf, Ağır Metal, İzoterm, Kinetik, Adsorption, Natural Material, Tuff, Heavy Metal, İsotherm, Kinetic
