Aluminas used for column chromatography or thin-layer chromatography are treated with acid or base to adjust the pH of a 10% slurry (w/v in water) to acidic, basic or neutral pH. These are designated by A, B or N, respectively. Acidic alumina has approximate pH 4.5, basic alumina has approximate pH 10.

https://www.sigmaaldrich.com/content/dam/sigma-aldrich/docs/Sigma-Aldrich/Product_Information_Sheet/a1772pis.pdf

After preparation (precipitation) alumina has an alkaline extract (up to pH 11) and neutral alumina is obtained from this material by washing with distilled water. When acidic alumina is required the adsorbent is adjusted with an acid in suspension until the extract has a pH of 4-6.

https://books.google.com.pk/books?id=P_MVjTFh16YC&pg=PA181&lpg=PA181&dq=preparation+of+basic+alumina+from+neutral+alumina&source=bl&ots=quJiUo6k2J&sig=33pReqc28JaRaqhKfHPC5DcEzKM&hl=en&sa=X&ved=0ahUKEwicgJ2c-PzLAhWBVBoKHbjOAIcQ6AEINTAF#v=onepage&q=preparation%20of%20basic%20alumina%20from%20neutral%20alumina&f=false

Please make a 10% slurry of neutral alumina in pH 10-11 NaOH solution and keep suspended for 24 h. then wash with 10 pH NaOH solution to remove the fines. I hope it may serve the purpose.

Hello..What do you mean by neutral alumina???

neutral alumna means Al2O3

Aluminas used for column chromatography or thin-layer chromatography are treated with acid or base to adjust the pH of a 10% slurry (w/v in water) to acidic, basic or neutral pH. These are designated by A, B or N, respectively. Acidic alumina has approximate pH 4.5, basic alumina has approximate pH 10.

https://www.sigmaaldrich.com/content/dam/sigma-aldrich/docs/Sigma-Aldrich/Product_Information_Sheet/a1772pis.pdf

After preparation (precipitation) alumina has an alkaline extract (up to pH 11) and neutral alumina is obtained from this material by washing with distilled water. When acidic alumina is required the adsorbent is adjusted with an acid in suspension until the extract has a pH of 4-6.

https://books.google.com.pk/books?id=P_MVjTFh16YC&pg=PA181&lpg=PA181&dq=preparation+of+basic+alumina+from+neutral+alumina&source=bl&ots=quJiUo6k2J&sig=33pReqc28JaRaqhKfHPC5DcEzKM&hl=en&sa=X&ved=0ahUKEwicgJ2c-PzLAhWBVBoKHbjOAIcQ6AEINTAF#v=onepage&q=preparation%20of%20basic%20alumina%20from%20neutral%20alumina&f=false

Please make a 10% slurry of neutral alumina in pH 10-11 NaOH solution and keep suspended for 24 h. then wash with 10 pH NaOH solution to remove the fines. I hope it may serve the purpose.

Thank you Mr. Ahmed for answering.