diff --git a/Schemas/NeuroML2/NeuroML_v2.2.xsd b/Schemas/NeuroML2/NeuroML_v2.2.xsd
index 85d7be9..4dc4e47 100644
--- a/Schemas/NeuroML2/NeuroML_v2.2.xsd
+++ b/Schemas/NeuroML2/NeuroML_v2.2.xsd
@@ -2149,17 +2149,6 @@
 
 
 
-    <!-- TODO: remove -->
-    <xs:complexType name="ConcentrationModel_D">
-
-        <xs:complexContent>
-            <xs:extension base="DecayingPoolConcentrationModel">
-
-                <xs:attribute name="type" use="required" fixed="decayingPoolConcentrationModel"/>
-
-            </xs:extension>
-        </xs:complexContent>
-    </xs:complexType>
 
     <xs:complexType name="IntracellularProperties">