Utilization of Biomass Waste of Pulp and Paper Industry for Production of Sodium Lignosulphonate (SLS)

The surfactant of sodium Lignosulphonate (SLS) is obtained from lignin isolation from the black liquor pulp and paper biomass waste. The obtained lignin is reacted with sodium bisulphite (NaHSO3) forming the SLS. This research studies the SLS synthesis process using three variables: temperature, pH and weight ratio of lignin and sodium bisulphite. Response surface methodology with the central composite design was used to optimize the process variables. The optimum conditions for making SLS from biomass-based lignin waste were obtained at 79.67°C, pH 8.32 and 4.58 bisulphite lignin ratio. Under these conditions, the highest yield of SLS was 89.96%. The SLS obtained has characteristics similar to SLS made from pure lignin with bisulphite. These characteristics include: water content 24.62% w/ w, ash content 32.23% w/w, organic compounds 41.76% w/w, volatile matter 5.14% w/w and density (solids) 1.12 g/mL. Based on the FTIR spectra, the resulting SLS also has similarities.