Suggest a procedure that could be used to remove lead (II) ions from industrial waste water as a precipitate. Provide an equation and explain your choice.
The idea here is that you know the solubility of ions, in this case Pb. PbCl2, PbCrO4, PbSO4, are three that are insoluble to varying degrees. Here is a simplified chart that will provide you with more information.
http://www.files.chem.vt.edu/RVGS/ACT/notes/solubility_rules.html
Awesome, thank you so much!!
To remove lead (II) ions from industrial wastewater as a precipitate, one commonly used procedure is the addition of sodium sulfide (Na2S) as a precipitating agent. This method relies on the reaction between lead (II) ions and sulfide ions to form lead sulfide (PbS), which is insoluble and can be easily separated from the water.
Here is the equation for the reaction:
Pb2+ + S2- → PbS (s)
Now, let's explain the choice of sodium sulfide (Na2S) as the precipitating agent:
1. Solubility of Lead Sulfide (PbS): Lead sulfide (PbS) is insoluble in water. This means that once it forms as a precipitate, it will not dissolve back into the water. Insolubility is essential for effective separation, as we want the lead (II) to be removed from the wastewater.
2. Sulfide precipitation: The reaction between lead (II) ions and sulfide ions is a well-known method for precipitating heavy metals, including lead. Sodium sulfide (Na2S) is commonly used because it is readily available, relatively inexpensive, and easily reacts with lead (II) ions to form insoluble lead sulfide (PbS).
3. pH control: The success of this precipitation process also relies on controlling the pH of the wastewater. For lead sulfide (PbS) to form effectively, the solution should be slightly basic (pH around 9-10). Therefore, it may be necessary to adjust the pH by adding an appropriate alkali, such as sodium hydroxide (NaOH), before adding sodium sulfide.
4. Separation of precipitate: Once the lead sulfide (PbS) precipitate forms, it can be separated from the wastewater through filtration or sedimentation techniques. The filtered solids can then be disposed of safely.
It should be noted that the chosen precipitation method will depend on the specific conditions and composition of the industrial wastewater. It is essential to consult with experts and follow appropriate guidelines and regulations when dealing with waste treatment processes.