Cultivation of Arthrospira platensis (ULC 0444) in varying concentrations of brewery influent wastewater_biochar analysis

This dataset presents the results of hydrothermal carbonization (HTC) performed on residual microalgal biomass obtained after anaerobic digestion. The microalgal biomass, grown in 90% brewery wastewater (WW) and processed for pigment extraction, underwent HTC at three different temperatures (180°C, 210°C, and 240°C) to assess its potential for biochar production and liquid phase valorization.

Experimental Details:

• Hydrothermal Carbonization (HTC):
  • Solid-to-liquid ratio: 1.5 g biomass per 32 mL anaerobically digested effluent.
  • HTC reactors: Small stainless-steel reactors (40 mL capacity) operated in a convection oven (Carbolite AX 30).
  • Reaction conditions: 180°C, 210°C, and 240°C for 3 hours.
  • Cooling method: Submerged in cold water post-reaction.
• Biochar Recovery:
  • Separation: Filtration using Whatman filter paper.
  • Measurement: Dried biochar mass used to calculate yield.

Biochar Characterization:

1. Thermal Stability:
   • Evaluated through Thermogravimetric Analysis (TGA).
2. Elemental Analysis:
   • C, H, N, S measured using a Flash 2000 Elemental Analyzer.
   • Samples processed in duplicate for accuracy.
3. ICP Analysis (ICP-OES; iCap 7000 Series Thermo Scientific, USA):
   • Biochar digested in concentrated HNO₃ and analyzed via ICP for elemental composition.
4. FTIR Spectroscopy (Nicolet, USA):
   • Functional group analysis for potential applications in adsorption and soil amendments.

Liquid Phase Characterization:

• • Bio-oil extracted from the aqueous phase using ethyl acetate.

Data Analysis:

• One-way ANOVA in Microsoft Excel was followed by a post hoc Tukey test to compare group means.

Data processing:
FTIR data was smooshed using available code from "https://github.com/cran/signal/blob/master/R/sgolayfilt.R"

The FTIR data were smoothed using the Savitzky-Golay algorithm in RStudio to enhance signal clarity while preserving peak features. The code was already existed in "https://github.com/cran/signal/blob/master/R/sgolayfilt.R"

The smoothing process involved the following steps:

1. The raw FTIR data, consisting of wavenumber and intensity values, were imported into RStudio.
2. The Savitzky-Golay filter was applied using the sgolayfilt() function from the signal package.
3. The filter was configured with a polynomial order of 3 and a window size of 201 points, ensuring an odd-length window for accurate filtering.
4. This method effectively reduced noise while retaining the integrity of spectral features, making the data suitable for further analysis.

Dataset Includes:

1. Biochar yield and thermal stability data.
2. Elemental composition results (C, H, N, S, and ICP analysis).
3. FTIR spectroscopy results for functional group identification.
4. Wastewater characteristics.

Purpose:
The dataset aims to evaluate the potential of HTC as a valorization pathway for residual microalgal biomass, supporting sustainable biochar production and the circular bioeconomy.