Resources

Carey et al. (2024) have claimed the 'longevity' of a GAC barrier for the immobilisation of PFAS is 30-40 years. This is based upon an infiltration rate which appears to be fabricated. 

I have developed a general analytical result for the effective CoP of multiple heat pumps cascaded in series, and the derivation of this is given in this document, along with some related observations.

I have suggested a 'league table' for the efficacy of solid adorbents for PFAS removal. The full explanation, along with associated commentary, can be found here.

Thie final published version of my article (jointly written by Prof Stoyan Karakashev) entitled 'Commercial-Scale Removal of Short-Chain PFAS in a Batchwise Adsorptive Bubble Separation Process by Dosing with Cationic Co-Surfactant'. I don't think for a minute that the use of CTAB as co-surfactant is practically viable because of its ecotoxicity, but the methods might be of interest to some. Note the concentrations required were much more than expected due to equivalence of charge considerations, and this is because of the significant complexity of the background matrix.

"Calculation of Cumulative Discounted Cash Flow as Applied to Notional Wind and Nuclear Power Projects." In early-August 2023 I saw an analysis that suggested that a notional nuclear energy project was significantly better than both onshore and offshore wind from a cash flow perspective, but, crucially, this assume a zero cost-of-capital. I posted a parallel analysis with discounted cash flows, and showed that the conclusions changed signicantly. I was asked to explain my methodology, so here it is. 

My letter, accepted at the journal 'Water Research', in which I discuss a recently published method for measuring adsorption isotherms that has been proposed by the a University of Queensland research team (Buckley et al., 2023). This document is the corrected proof.

 I’ve become aware that some people in the activated carbon and remediation communities don’t know what an adsorption isotherm. In the spirit of doing-is-understanding, I prepared this very brief guide about how you yourself can prepare and adsorption in the lab.

I don’t suppose that many will actually perform experiments, although, if you do, your data will be very gratefully received by me. However, if you are interested, have a 5-minute read; it is hoped you’ll get a still deeper understanding of adsorption isotherms. 

On 18th June 2023 Paul Stevenson posted on LinkedIn to demonstrate that activated carbon is not ‘used-up’ during the in-situ immobilisation of PFAS due to the pumping of an activated carbon slurry into the ground, but instead reaches an equilibrium with the local bulk concentration. This analysis is herein extended to PFOS. It is acknowledged that there is some more detail that is required to fully explain the analysis, and this will be  posted a ‘white paper’ very soon. 

An SPT 'white paper' from October '22 '‘Biopersistency’ of PFAS in a Highly-Stylised Living Organism'. We explore, from the perspect of of a chemical engineer, the terms associated with and explain why 'long-chain' PFAS is rejected via the bowel whereas short-chain PFAS is rejected via the kidney.

Cite as:

Stevenson P 2022 Biopersistency in a Highly-Stylised Living Organism, SPT White Paper 2

In summer '22 my piece 'Bidding Farewell to the Forever Chemicals' was published in the Institution of Chemical Engineers magazine 'The Chemical Engineer'. Some might find it an interesting introduction to adsorptive removal methods. By the way, I was silly to use the term 'Forever Chemicals', because PFAS can be degraded. It was for this piece that Paul Stevenson recieved a nomination for the 2023 Institution of Chemical Engineers Hanson Medal.

Cite as:

Stevenson P 2022 Bidding Farewell to the Forever Chemicals, The Chemical Engineer 973/ 974, 44-8