title: Assessment of the effectiveness of orange (Citrus reticulata) peel in the recovery of nickel from electroplating wastewater.
abstract: BACKGROUND
  Wastewater discharged from electroplating industry contains different concentrations of heavy metals, which when released into the environment pose a health hazard to human beings.
  
  
  OBJECTIVE
  The aim of this study was to assess the effectiveness of orange peel as an adsorbent in the recovery of Nickel (Ni) from electroplating wastewater.
  
  
  METHODS
  The effectiveness of orange peel as an adsorbent was assessed by determining the optimum conditions of adsorption (adsorbent dose, pH, and contact time), calculating the recovery percentage, and characterizing the orange peel sludge resulting from adsorption/desorption process as being hazardous or not.
  
  
  RESULTS
  Under optimum conditions for adsorption, orange peel was found to be an effective adsorbent of Ni from electroplating wastewater. It achieved 59.28% removal of the metal from a solution containing 528 mg/l, at a dose of 60 g/l, at pH 7, and for 1-h contact time. The nickel uptake capacity of orange peel was calculated to be 5.2 mg/g. Using HCl for desorption of adsorbed Ni, a recovery of 44.46% of Ni discharged in the wastewater could be reached. Orange peel resulting from the adsorption/desorption process was characterized as being nonhazardous.
  
  
  CONCLUSIONS
  Orange peel was found to be effective in the recovery of nearly half of the amount of Ni discharged in electroplating wastewater. Further studies are required to determine (a) the impact of the recovered NiCl2 solution on the quality of the plated product, (b) the effect of activation of orange peel on the adsorption process, and (c) the number of cycles during which orange peel can be reused as an effective adsorbent.
authors.affiliation: Environmental Health Department, High Institute of Public Health, Alexandria University, Alexandria, Egypt.
authors.forename: Rim A
authors.initials: RA
authors.lastname: Hussein
mesh_terms: D000327:Adsorption; D002957:Citrus / Q000737:chemistry*; D004595:Electroplating; D006801:Humans; D006863:Hydrogen-Ion Concentration; D009532:Nickel / Q000032:analysis* / Q000737:chemistry*; D014865:Waste Disposal, Fluid / Q000379:methods*; D062065:Wastewater / Q000032:analysis*; D014874:Water Pollutants, Chemical / Q000737:chemistry
chemical_list: D009532:Nickel; D062065:Wastewater; D014874:Water Pollutants, Chemical