  We report herein, the potential of raw pinecone powder (PCP) and pinecone
biochar (PCBC) as alternatives to activated carbon used in Permeable Adsorptive
Barriers (PABs) for the in situ remediation of polluted groundwater. A
constructed lab-scale unconfined aquifer ($38\times30\times17$ $cm$) fitted
with PCP and PCBC PABs ($21\times3\times20$ $cm$), was evaluated for the
removal of $Pb^{2+}$ ions in a continuous flow setup. Results indicate that
after $3600$ minutes, PCP was able to reduce $Pb^{2+}$ ions from a Co=$50$
$mg/L$ to $7.94$ $mg/L$ for the first run and $19.4$ $mg/L$ for a second run,
respectively. Comparatively, PCBC reached $6.5$ $mg/L$ for the first run and
$8.94$ for the second run. It was confirmed that adsorption was best described
by the first-order kinetic model with $R^2$ values above $0.95$. Maximum
adsorption capacity values were found to be $1.00$, $0.63$, $1.08$, and $0.85$
mg/g for each scenario respectively. In addition, nonlinear regression models
of exponential and Gaussian Processes are fit to explain remediation by time
for $Pb^{2+}$ and Methylene Blue. Gaussian Processes are able to better explain
the variation of pollution removal compared to simpler exponential models. When
regressed against true removal percentages all models are able to provide
$R^2>0.99$.
