I regret to share that the support for deleting column is currently unavailable in Asspose.Slides. Kindly, visit this thread
for work around and your further knowledge. An issue with ID SLIDESNET-17324 has been created to resolve the issue in Aspose.Slides for .NET. Once resolved in Aspose.Slides for .NET, it will be ported to Aspose.Slides for Java as well. I have created an issue with ID SLIDESJAVA-33164
to provide this feature in Aspose.Slides for Java. I will share the further information with you as soon as the issue will be resolved. Meanwhile, you may persist with work around method in the shared link. The code is although in .NET, but you may understand the logic and implement the same for Java hopefully.