Premium
The enhancement of black liquor treatment by applying a natural flocculant and converting its sludge to a high‐benefit product
Author(s) -
Amriani Feni,
Bani Okta,
Muryanto Muryanto,
Sari Ajeng Arum,
Sudiyani Yanni
Publication year - 2019
Publication title -
the canadian journal of chemical engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.404
H-Index - 67
eISSN - 1939-019X
pISSN - 0008-4034
DOI - 10.1002/cjce.23300
Subject(s) - carbonization , flocculation , black liquor , chemistry , adsorption , pulp and paper industry , chitosan , waste management , nuclear chemistry , chemical engineering , lignin , organic chemistry , engineering
Black liquor (BL) as lignocellulosic‐based industrial wastewater is largely attained from a chemical pretreatment process. When treated with the commonly used coagulant polyaluminum chloride (PACl), BL was decolourized but its pH decreased drastically from 13 to 4–5. Chitosan as a natural flocculant was added to the BL treatment process to support the PACl. The combination of coagulant‐flocculant (PACl‐Chitosan) effectively generated sludge, rejuvenated the treated BL pH level to neutral, and decolourized and reduced several parameters required for the treated BL disposal. To establish a sustainable recycling process and enhance the BL treatment, the generated sludge as a potential source was recovered and converted to a carbonaceous adsorbent (CA) by applying a two‐stage carbonization process, heat and steam carbonization, during which the temperature and time in the first stage of the heat‐carbonization process differ. The first BL sludge‐based CA (BLS‐CA 1) is produced by employing the first stage heating at 575 °C for 180 min while the second black liquor sludge‐based CA (BLS‐CA 2) is produced by employing the first stage heating at 450 °C for 60 min. Both CAs were able to adsorb about 99 % methylene blue (MB) at MB concentration 100 mg/L for 16 h though they have smaller surface areas than commercially activated carbon, which is only able to adsorb about 70 % MB at the same concentration and adsorption time. This study demonstrates a potential way to reduce the emerging problem from the generated sludge through a sustainable recycling process as well as BL treatment.