Effects of Operational Variables on the Pulp Yield and Lignin Dissolution of Cyperus Ar-ticulatus

The influence of operational variables on the pulp yield and lignin dissolution of Cyperus articu-latus was studied. The study was aimed at optimizing pulping variables and selecting suitable delignification conditions for the production of pulp and paper from the plant. Cyperus articula-tus chips were delignified in a laboratory pulpwood digester under the soda pulping process us-ing the following pulping conditions: time (30 – 150 minutes), temperature (120 – 150oC), liquor to solid ratio (10:1 – 20:1) and concentration of cooking liquor (4 – 6% caustic soda). Experi-mental data were fitted into a central composite design and the polynomial equation derived re-produced the pulp yields and the residual lignin contents with errors less than 6%. Optimum pulp yields were obtained using low values of the process variables while the reverse was the case for the residual lignin. Pulping at high temperatures for a short cooking time with low to medium concentration of pulping liquor gives the best compromise for both pulp yield and resid-ual lignin content.Keywords: Cyperus articulatus, soda pulping, pulp yield, residual lignin

A bibliometric description of lignin applicability for the removal of chemical pollutants in effluents

Several industrial sectors produce tons of effluents daily containing a high amount of hazardous chemical pollutants that pose a major threat to the environment and human health. Current wastewater treatment methods, such as flocculation and activated carbon adsorption, have drawbacks linked to high material cost and too much energy consumption. Thus, the search for renewable, biodegradable, and efficient materials has been the object of research aimed at replacing the conventional materials used to cheapen processes and reduce environmental impacts. Lignin stands out in this context as it has low cost and high availability. Therefore, several scientific researches were developed to harness the potential of lignin, especially as adsorbent, for the removal of chemical agents from effluents. This paper presents a bibliometric review performed on the Scopus database, showing the evolution of studies related to the applicability of lignin in the removal of chemical pollutants in waters over the last five years. Data regarding annual publications, languages, journals, countries, institutions, keywords, and subjects were analyzed. The realized screening selected 130 articles that met the previously defined criteria. Results indicated a strong collaboration between countries and China's substantial contribution to the documents. The analysis also has shown that lignin is mainly used as adsorbent material, sorbent, flocculant agent, and hydrogel and presents important results and information for future researchers on this topic.The authors acknowledge financial assistance from the Brazilian research funding agencies such as CAPES (Coordination for the Improvement of Higher Education Personnel) under Finance Code 001, a Brazilian foundation within the Ministry of Education (MEC), CNPq (National Council for Scientific and Technological Development), a Brazilian foundation associated to the Ministry of Science and Technology (MCT), and FAPITEC/SE (the Foundation of Support to Research and Technological Innovation of the State of Sergipe).info:eu-repo/semantics/publishedVersio