I am trying to replace a value in a pandas dataframe cell that I am constructing from a JSON file that I get from Airtable API the JSON file looks like this one:

Obviously this is a sample and I am replacing the real keys and some values, because they are from a private application, but what I am trying to do once I get the API response and then convert the JSON into a dataframe using the code below, is to replace the values {"specialValue": "Infinity"} from roi key and {"specialValue": "NaN"} from investment_return key with zeros:

Then once I have the JSON data converted into a dataframe I am trying to replace the values using this code:

df.replace('{"specialValue": "Infinity"}', np.nan, inplace=True)

For some reason is not working:

Can somebody give me a possible approach on how to convert those into zeros?