Moxa combustion waste and its bio activities on cotton -- a facile and green finishing process towards a sustainable and value adding application for medical textile

Abstract

Moxibustion therapy is a popular treatment for various diseases in traditional Chinese medicine. It is known that the combustion byproduct of moxa ash from moxibustion therapy has various medicinal properties, however its application has been largely ignored. This paper developed a simple, green and effective process for finishing cotton with biomass waste of moxa ash. Bio performance of finished cotton and its value adding applications were explored. A comparison is made between moxa extracts and moxa ash, with functions such as anti-ultraviolet, antioxidant and antibacterial properties investigated. Results show that although compared with moxa extracts dyed cotton, moxa ash finished cotton lost certain strength in anti-ultraviolet and antioxidant activities due to decomposition of certain effective bio substances during combustion, it exhibited better performance than that of untreated cotton used as control, with UPF increased from 24 to 98 and ABTS·⁺ percentage radical scavenging from 8.5% to 13.7%. Results of antibacterial activity of moxa ash finished cotton is a highlight in this work. It is seen that while it is less effective in inhibiting fungus such as C. albicans, the moxa ash finished cotton is as effective (> 99% bacterial removal) as its moxa extracts counterpart in antibacterial activity against Gram-positive bacterial such as S. aureus and B. cereus, as well as in inhibiting certain type of Gram-negative bacterial strain such as E. coli. These outcomes have opened up a broad application of moxa ash as biomass waste in textile industry for medicare and healthcare use.