The Effectiveness of Moringa oleifera Seed Flour and Chitosan as Coagulant‐Flocculants for Water Treatment

Abstract

The aim of this contribution is to provide a comprehensive comparison between chitosan and Moringa oleifera seed flour (MOSF) as coagulant-flocculants. MOSF was obtained as a byproduct in a biodiesel process. Turbidity and heavy metal ion removal, using both ecofriendly materials, was assessed. Jar tests were performed on samples taken from river water, agricultural wastewater, and mixed wastewater (contaminated with agricultural and urban residues). Bioflocculant dosages within the range of 0.005-20 mg L À1 were tested. Irrespective of the initial turbidity, the optimal dosage of chitosan and MOSF for decreasing turbidity in river water was 1 and 5 mg L À1 , respectively. Furthermore, from river water, Pb removal up to 95% was achieved irrespective of the bioflocculant; for Mn removal, MOSF performed better than chitosan, with the adsorbent trapping close to 90% of this metal. MOSF decreased turbidity levels and heavy metal content (Mn and Pb) to under the permissible limits (Mexican environmental regulation for potable water, NOM-127-SSA1-1994). Additionally, kinetic data were fitted to kinetic models of adsorption for the pollutants. For agricultural wastewater, a chitosan dosage of 10 mg L À1 reduced turbidity to 5-10 nephelometric turbidity units (NTU), and a MOSF dosage of 10 mg L À1 decreased the turbidity to values lower than 5 NTU. For the mixed wastewater, chitosan achieved a high turbidity removal, while MOSF was not suitable.

Simultaneous removal of Cd, Co, Cu, Mn, Ni, and Zn from synthetic solutions on a hemp‐based felt. III. Real discharge waters

“…Abundant data can be found in the literature summarized in various reviews. [12][13][14][15][16][17][18] The last decade has also shown an explosion in the development of new adsorbents produced from plant-based sources such as hemp. Hemp, Cannabis sativa L., is an annual high yielding crop grown for its fibers and seeds, which find numerous applications.…”

Clarification of the water of wetlands using a mixture of natural coagulants

“…These seeds remove 88.8 and 95.7 turbidity when the water initially has 36 and 70 NTU, respectively. When using 0.5 mg/L of chitosan, 83.3% of the initial turbidity is removed, 36 UBNT, however, when the initial turbidity of the water is 70 NTU, a removal of 88.8% is obtained when 1 mg/L of chitosan is used [20].…”

Coupling Extracts of Plant Coagulants With Solar Disinfection Showed a Complete Inactivation of Faecal Coliforms

“…Plant‐based coagulants and disinfectants have enormous advantages in water treatment. Plant‐based coagulants produce less sludge volume than alum, require no pH adjustment, and there is no toxicological concern . They are of great interest for low‐cost water treatment in comparison to chemical coagulants and help provide pure water for populations in developing countries who rarely have access to it.…”

“…Plant-based coagulants produce less sludge volume than alum, [34] require no pH adjustment, [28] and there is no toxicological concern. [26,27] They are of great interest for low-cost water treatment in comparison to chemical coagulants [19,27] and help provide pure water for populations in developing countries who rarely have access to it. Usage of natural products also reduces the formation of disinfectants that threaten human health, as their by-products are organic, biodegradable, and reduce risk during handling.…”

“…The plant extracts are often available locally, acceptable, easy to use, and there is no toxicological concern as mostly used in traditional medicine; hence, a low-cost alternative to chemical coagulants. [26,27] Plant-based coagulants also do not require pH adjustment compared with inorganic coagulants and provide extra cost saving. [28] Edible and other useful oils may be extracted from M. stenopetala before the coagulant is fractionated.…”