The above table comes from European Medicine Agency, the equivalent of the FDA.  

Interesting and novel approach is outlined in a recent OPRD article from Merck http://pubs.acs.org/doi/abs/10.1021/op2001657 
Screening Binary Systems of Chelating Agents Combined with Carbon or Silica Gel Adsorbents: The Development of a Cost-Effective Method to Remove Palladium from Pharmaceutical Intermediates and APIs by  Lijun Wang


The approach is certainly worth considering on small scale.  Basically, they are using homogeneous chelating agents to capture to metal and then adsorbing this onto a solid surface for filtration.  They note, this approach could be economical on scale, especially considering many commercially available scavengers cost $1000's/kg at scale.  

 We agree - one of the main issues on silica is high cost, especially considering silica unlike ion exchange resins has relatively low loading so a lot of it is potentially needed.  One of the benefits of the PhosphonicS technology is it is one step with a very low cost of manufacture enabling competitve pricing below $1000/kg for bulk orders.  Not quite as low as offered by this Merck approach, but also the Merck approach requires more effort in terms of processing and development.  So overall probably equal.   

A nice review by the journal Nature was published at the start of the year reviewing the pharmaceutical industry research efforts.  It is a short article, only 2 pages long, so no need to summarize.  Follow the link to download the paper or look it up - "A decade of Change by John Arrowsmith, Nature Reviews, Volume 11 page 17" 

PhosphonicS was at OPRD in Budapest - the organizer made a short video and part of it features our exhibit.  

Heraeus and PhosphonicS have a strategic partnership that allows customers with low-grade precious metals stream access to both PhosphonicS immobilized ligand technology to capture the metal and Heraeus's batch refining process.  The result is the economic capture of metals with clear identity throughout the refinining process ensuring the customer a high degree of transparency.