Utilizing mining dam bottom sludge as a novel adsorbent for AuO removal from wastewaters: Batch and Column studies


Dişli E. , Öztürk D. , Aladağ E.

Journal Of Molecular Liquids, vol.338, pp.1-15, 2021 (Journal Indexed in SCI Expanded)

  • Publication Type: Article / Article
  • Volume: 338
  • Publication Date: 2021
  • Doi Number: 10.1016/j.molliq.2021.116644
  • Title of Journal : Journal Of Molecular Liquids
  • Page Numbers: pp.1-15

Abstract

In  this  study,  the  adsorption  of  Auramine  O  (AuO)  dye  using  bottom  sludge  (BS)  was investigated in batch and continuous systems. The BS was characterized by EDX, BET, XRD, DLS, ζ-potential, SEM, FTIR, helium pycnometer, and mercury porosimetry. The kinetic and isotherm  data  were  fitted  to  pseudo-second-order  and  Langmuir  models.  The  maximum amount   of   adsorption   calculated   from   the   Langmuir   isotherm   model   was   5.09   mg/g. Thermodynamic    studies    showed    that    adsorption    was    endothermic    and    occurred spontaneously. Thomas, Clark, and Yoon-Nelson models were suitable (R²>0.95 for all these models)  to  explain  the  dynamic  behavior  of  AuO-BS  in  the  column  system.  Increased  bed depth  increased  breakthrough  time,  while  the  breakthrough  time  declined  with  increased initial  AuO  concentration  and  flow  rate.  Optimum  conditions  were  determined  for  the  batch system  as  4  g  of  BS  dose,  100  rpm  agitation  speed,  and  90  min  reaction  time;  optimum conditions for the column system were 3 cm bed depth, 0.14 mL/min flow rate, reaction time of 181 h; and optimum conditions for both systems were 100 mg/L AuO concentration, 20 °C reaction  temperature  and  pH  6.18  (natural).  Under  these  conditions,  the  amounts  of  AuO adsorbed  in  batch  and  column  systems  were  calculated  as  2.06  mg/g  (89.75%)  and  2.634 (47.13%)  mg/g,  respectively.  The  studies  showed  that  efficient  remediation  of  AuO  from aquatic environments is possible with BS.