Bioremediation of a Complex Industrial Effluent by Biosorbents Derived from Freshwater Macroalgae

Abstract

Biosorption with macroalgae is a promising technology for the bioremediation of industrial effluents. However, the vast majority of research has been conducted on simple mock effluents with little data available on the performance of biosorbents in complex effluents. Here we evaluate the efficacy of dried biomass, biochar, and Fe-treated biomass and biochar to remediate 21 elements from a real-world industrial effluent from a coal-fired power station. The biosorbents were produced from the freshwater macroalga Oedogonium sp. (Chlorophyta) that is native to the industrial site from which the effluent was sourced, and which has been intensively cultivated to provide a feed stock for biosorbents. The effect of pH and exposure time on sorption was also assessed. These biosorbents showed specificity for different suites of elements, primarily differentiated by ionic charge. Overall, biochar and Fe-biochar were more successful biosorbents than their biomass counterparts. Fe-biochar adsorbed metalloids (As, Mo, and Se) at rates independent of effluent pH, while untreated biochar removed metals (Al, Cd, Ni and Zn) at rates dependent on pH. This study demonstrates that the biomass of Oedogonium is an effective substrate for the production of biosorbents to remediate both metals and metalloids from a complex industrial effluent.

The industrial ecology of freshwater macroalgae for biomass applications

“…Biochar produced from freshwater macroalgae can also be used as a biosorbent that effectively binds metals [35,36]. Alternatively, the biomass can be treated with an iron (Fe) solution prior to conversion to biochar to produce a biosorbent that effectively binds metalloids [35][36][37].…”

“…Alternatively, the biomass can be treated with an iron (Fe) solution prior to conversion to biochar to produce a biosorbent that effectively binds metalloids [35][36][37]. The sequential application of biochar and Fe-treated biochar can then be used to comprehensively remove metals and metalloids from a range of industrial wastewaters [36].…”

“…Cultivation conditions Temperature (°C) 5.8 32.1 [9,11,12,[14][15][16]42,57,58] Water flow rate (volumes day −1 ) 0 (batch culture) 5.0 [9,11,12,[14][15][16][17]35 [11,12,[39][40][41][42]48,58] respectively) with high energy potential (HHV of 33.7 and 33.5 MJ kg −1 respectively) when processed using hydrothermal liquefaction [13,39]. Furthermore, the quality of the biocrude can be improved through selective post-harvest processing to reduce the quantities of heteroatoms (N + S) [31].…”

“…2C) [13,14,17,52]. The resultant biomass can then be dried or converted to biochar and used as a biosorbent to further treat these metal-rich wastewaters [35,36]. The biochar can also be used as an ameliorant for low-fertility soils, for example to aid in mine site rehabilitation [23].…”

OPTIMIZATION OF Cr AND Cu BIOSORPTION BY GREEN MARINE ALGAE Caulerpa racemosaVar. Cylindracea & Ulva lactuca

“…The potential of seaweeds as biosorbents for removal of heavy metal has been studied by various scientists in recent years offers continuous availability and reusability of sorbent in numerous cycles. Brown and green seaweeds are studied most for the biosorption research [16] [17]. Nasab et al, 2017 [18] reported 53 to 80 % of metal removal efficiency for 0.1 to 0.5 g/l of biomass of Gracillaria corticata.…”