Leather and Footwear Journal

Volume 20, no 3

Contents
- Contents PDF
Full issue
- Full issue
EFFICIENCY OF ELECTROCOAGULATION METHOD TO REDUCE COD, BOD AND TSS IN TANNERY INDUSTRY WASTEWATER: APPLICATION OF THE BOX–BEHNKEN DESIGN
- Pages 217-228
  Edwar AGUILAR-ASCÓN¹*, Liliana MARRUFO-SALDAÑA², Walter NEYRA-ASCÓN¹
  - ¹Universidad de Lima, Instituto de Investigación Científica (IDIC), Av. Javier Prado 4600, Surco, Lima, Perú; e-mails: eaguilaa@ulima.edu.pe; wneyraa@gmail.com
  - ²Centro de Innovación Productiva y Transferencia Tecnológica del Cuero, Calzado e Industrias Conexas (CITEccal Lima) - ITP, Av. Caquetá 1300, Rímac, Lima, Perú; lmarrufo@itp.gob.pe
  ABSTRACT. This study intends to assess the removal efficiency of the chemical oxygen demand (COD), biochemical oxygen demand (BOD), and total suspended solids (TSS) from raw tannery wastewater using electrocoagulation by aluminum electrodes as well as to determine the effects of its main operating factors. Therefore, the response surface methodology was applied through an experimental Box–Behnken design by considering the current intensity (I), treatment time (T), and pH levels as the factors. In addition, the BOD, COD, and TSS removal percentages were considered to be the response variables. The results indicate that the treatment time, current intensity, and pH level were significant for COD and TSS, whereas only the treatment time was significant at a confidence level of p-value < 0.05 for BOD. For COD, the optimal operating conditions were I = 3 A, T = 24 min, and pH = 8.4; for BOD, the optimal operating conditions were I = 3 A, T = 24 min, and pH = 5.5; and for TSS, the optimal operating conditions were I = 2.7 A, T = 19 min, and pH = 7.4. Under these conditions, removal efficiencies of 56.8%, 69.2%, 99.9% were observed for COD, BOD, and TSS, respectively. The results suggest that electrocoagulation is an effective method for removing the parameters under study; therefore, it is a viable alternative for reducing the pollution issues caused by the tannery industry.
  
  KEY WORDS: tannery, electrocoagulation, aluminum electrodes, Box–Behnken design
  Read article
AN IMPROVED HALO METHOD FOR EVALUATING THE ANTIBACTERIAL ACTIVITY OF LEATHER
- Pages 229-236
  Jinwei ZHANG^{1, 2}, Qiuyue TANG^{1, 2}, Wuyong CHEN^{1, 2}, Hongbin SUN³,Qiming OU⁴, Yonghan WEN^{4, *}
  - ¹National Engineering Laboratory for Clean Technology of Leather Manufacture, Sichuan University, Chengdu 610065, P. R. China
  - ²The Key Laboratory of Leather Chemistry and Engineering of Ministry of Education, Sichuan University, Chengdu 610065, P. R. China
  - ³Guangdong Shengfang Chemical Corporation, Jiangmen 529162, China
  - ⁴Guangdong Jiangmen Supervision Testing Institute of Quality and Metrology, Jiangmen 529000, China
  ABSTRACT. In order to evaluate leather antibacterial activity rapidly and accurately, an improved halo method was developed based on conventional halo method and the agar diffusion plate method. During the new method, there were two layers of medium, the bottom was sterile medium and the top was medium containing microbes; more than one leather sample could be tested in a culture dish. The antibacterial activities of leather treated by nano-silver, nano-ZnO and butyl paraben against Escherichia coli, Staphylococcus aureus, Aspergillus niger and Rhodotorula mucilaginosa were tested by the new method. The results indicated intraclass correlation coefficient values were greater than 0.7 but the P values were less than 0.05 during improved halo method testing, thus, the repeatability and reliability was comparable or even better than conventional method. Nano-silver showed excellent and broad antibacterial activity and the difference between each antibacterial agent could be observed clearly and intuitively during improved halo method testing. In sum, improved halo method was a fast, accurate, qualitative and quantitative testing method and would be a new choice for evaluating leather antibacterial activity.
  
  KEY WORDS: leather, antibacterial activity, evaluation method, improved halo method
  Read article
ANTIBACTERIAL COMPOUND BASED ON SILICONE RUBBER AND ZnO AND TiO₂ NANOPARTICLES FOR THE FOOD AND PHARMACEUTIC INDUSTRIES. PART II - BIOLOGICAL AND MORPHOLOGICAL CHARACTERIZATION
- Pages 237-244
  Mihaela NIŢUICĂ (VÎLSAN)^{1, *}, Maria SÖNMEZ¹, Mihai GEORGESCU¹, Maria Daniela STELESCU¹, Laurenţia ALEXANDRESCU¹, Dana GURĂU¹, Carmen CURUŢIU^{2, 3}, Lia Maria DIŢU^{2, 3}
  - ¹INCDTP - Division Leather and Footwear Research Institute, 93 Ion Minulescu St., sector 3, Bucharest,mihaela.nituica@icpi.ro, mihaelavilsan@yahoo.com
  - ²University of Bucharest, Faculty of Biology, 1-3 Portocalelor St., 6th district, 060101, Bucharest, Romania
  - ³Research Institute of University of Bucharest, 36-46 M. Kogalniceanu St., 5th district, 050107, Bucharest, Romania
  ABSTRACT. The aim of this paper is the biological and morphological characterization of an antibacterial compound based on silicone rubber (Elastosil R701/70-OH), reinforced with ZnO and TiO₂ nanopowders (with antibacterial, antifungal and antimicrobial properties), charged (chalk), crosslinked with peroxide (dicumyl peroxide - powder 40% with calcium carbonate and silica, specific to the food, pharmaceutical, but also medical field). ZnO and TiO₂ nanopowders, by their homogeneous dispersion in the mass of the compound, have a determined role on its antibacterial and antimicrobial sterilization properties. The mixture of antibacterial compound based on silicone rubber was made on a laboratory roller, provided with cooling, in the form of a sheet (maximum thickness 5 mm), in strict compliance with the technological recipe and the established mode of operation. Subsequently, the mixture is processed into forming molds at predetermined parameters by determining the vulcanization time using the Monsanto rheometer (to determine the optimum temperature and vulcanization times), but also the biological and morphological characterization, according to current standards in specific food and pharmaceutical environments.
  
  KEY WORDS: silicone elastomer, biological characterization, nanopowders, antibacterial
  Read article
GREEN PRODUCTIVITY IN THE INDONESIAN LEATHER-TANNING INDUSTRY
- Pages 245-266
  Febriani PURBA^{1, 2}, Ono SUPARNO², Ani SURYANI²
  - ¹Department of Agroindustrial Technology, Faculty of Agriculture, University of Lambung Mangkurat, Jl. Ahmad Yani Km. 36, Banjarbaru, South Kalimantan, Indonesia, purba_febriani@apps.ipb.ac.id
  - ²Department of Agroindustrial Technology, Faculty of Agricultural Engineering and Technology, IPB University, Jl. Raya Dramaga, Dramaga Kampus, Dramaga, Bogor 16680, West Java, Indonesia
  ABSTRACT. Green productivity (GP) is a strategy by which production processes are improved by efficiently using resources and materials and adverse impacts on the environment are reduced. This study aims to measure GP of an Indonesian leather-tanning industry and develop alternatives to current processes that would improve its environmental and economic impacts. Two small to medium tanneries (Tanneries A and B) in two provinces were used as a case study. Data were collected through direct observation, measurements, in-depth interviews, and activity documentation. Material flow was analyzed using a green material flow map to determine the six sources of green wastes and the environmental indicators. The GP Index (GPI) was used to measure GP. The best method by which to improve GP was determined using GPI to a ratio of GP along with expert analysis using an analytical hierarchy process. GPI at Tannery A, located in West Java, was 0.14 with economic and environmental indicators of 1.44 and 10.41, respectively. GPI at Tannery B, located in Central Java, was 0.16 with economic and environmental indicators of 1.60 and 9.99, respectively. GP in both tanneries was low because of their suboptimal use of water. High water consumption can lead to a high discharge of liquid waste. Six alternatives for Tannery A and four for Tannery B were created. According to GPI, GP ratio, and expert opinion, the best strategy by which to improve GP was water recycling in the soaking and liming processes. This strategy increased GPI at Tannery A to 0.18 and at Tannery B to 0.20.
  
  KEY WORDS: Green productivity, Green productivity index, Green productivity ratio, Indonesian leather-tanning industry lining
  Read article
KERATIN HYDROLYSATES EXTRACTED FROM SHEEP WOOL WITH POTENTIAL USE AS ORGANIC FERTILIZER
- Pages 267-276
  Mariana Daniela BERECHET^{1, *}, Demetra SIMION¹, Maria STANCA¹, Cosmin-Andrei ALEXE¹, Ciprian CHELARU^,, Maria RÂPĂ²
  - ¹INCDTP – Division: Leather and Footwear Research Institute, 031215 Bucharest, Romania, marianadanielaberechet@yahoo.co.uk; demetra.simion@yahoo.com; maria.stanca@icpi.ro; cosminandrei.alexe@yahoo.com; ciprian.chelaru@icpi.ro
  - ²Politehnica University of Bucharest, 060042, Romania, rapa_m2002@yahoo.com
  ABSTRACT. Keratin hydrolysates were obtained from sheep wool by alkaline hydrolysis at different concentrations of KOH (3%, 5% and 8%) and temperatures (75°C, 85°C, 95°C and 99°C) of the reaction medium. The protein content of the keratin extracts was between 65.54% and 87.10%. Particle measurements showed a decrease in particle size with the increase of concentration and temperature of the reaction medium. The ATR-FTIR spectra revealed specific bands to proteins and sulfur originated from keratin amino acids. The keratin hydrolysate type KerK8₉₅ was further investigated as organic fertilizer for two types of wheat seeds. The results showed that the use of 5% KerK8₉₅ led to the increase of the wheat stems lengths by 10.7% for Mirastar wheat and 18.3% for Tamino wheat, respectively, compared to control sample. Keratin hydrolysates are promising biopolymers as organic fertilizers in agriculture applications
  
  KEY WORDS: keratin hydrolysates, protein substance, organic fertilizer
  Read article
TECHNOLOGY OF FREE CHROME TANNING PROCESS: OPTIMAL LEVEL OF FORMALDEHYDE AS TANNING AGENT FOR MONDOL STINGRAY (Himantura gerrardi)
- Pages 277-286
  Laili RACHMAWATI*, Emiliana ANGGRIYANI, Nur Mutia ROSIATI
  - Department of Leather Processing Technology, Politeknik ATK Yogyakarta, Sewon, Bantul, 55281, D.I. Yogyakarta, Indonesia, lailirachma@gmail.com
  ABSTRACT. Chrome (VI) has a high level of toxicity. Formaldehyde is potential to be developed as a substitute of chrome tanning agent. The aims of this study are to explain the amount of formaldehyde bound, shrinkage temperature, tensile strength, and tear strength on Mondol stingray (Himantura gerrardi) leather. Pickled mondol stingray has been used as raw material. The study was divided into 4 treatments, that is P.I (formaldehyde 2%), P.II (formaldehyde 4%), P.III (formaldehyde 6%), and P.IV (formaldehyde 8%). The method used is drum tanning. Shrinkage temperatures, tensile strength and tear strength of P.I and P.II are significantly different from P.III and P.IV, but P.I is not significantly different from P.II, whereas P.III is not significantly different from P.IV. P.III is shown to improve the quality of leather stingray more than P.I and P.II, and has fulfilled the requirements of leather stingray according to SNI. 06-6121-1999. It can be concluded that the optimal level of formaldehyde tanning agent that can be used as a chrome tanning agent substitute in tanning Mondol stingray skin is formaldehyde 8% (P.III).
  
  KEY WORDS: free chrome tanning agent, formaldehyde, Himantura gerrardi
  Read article
PREPARATION AND APPLICATION OF MODIFIED MONTMORILLONITE DISPERSION FOR CHROME-LESS TANNING OF LEATHER
- Pages 287-300
  Maryna ZHALDAK*, Olena MOKROUSOVA
  - Kyiv National University of Trade and Economics, Kyoto str., 19, 02156, Kyiv, Ukraine, maryna070992@ukr.net
  ABSTRACT. The properties of modified montmorillonite dispersions for their use in the chrome-less leather tanning method were investigated. It is proposed to modify montmorillonite with aluminum compounds and to combine the obtained dispersions with chromium compounds for leather treatment. Modification of montmorillonite dispersions by aluminum compound within 5.0-7.0% Al₂O₃ of the weight of the mineral contributes to obtaining the most stable positively charged montmorillonite dispersions. The use of the obtained montmorillonite dispersions is effective for stabilizing the collagen structure and increasing the temperature resistance of collagen. The use of modified montmorillonite dispersions combined with a chromium tanning agent contributes to the introduction of chrome-less tanning. 0.75% of Сr₂O₃ and 3.0% of modified dispersion of montmorillonite of the weight of the pelts in conversion for mineral weight are considered the optimal consumption of chromium tanning agent.
  
  KEY WORDS: tanning, montmorillonite, potassium aluminum sulfate, modification, dispersion, collagen, leather properties
  Read article
INTEGRATING ROMANIAN FOOTWEAR COMPANIES IN A SUSTAINABLE APPRENTICESHIP SYSTEM AND EXPERIENCE FROM PILOTING WORK BASED LEARNING
- Pages 301-312
  Bogdan SÂRGHIE¹, Andreas SANITER², Arina SEUL¹, Aura MIHAI^{1, *},
  - ¹“Gheorghe Asachi” Technical University of Iasi, Faculty of Industrial Design and Business Management, Blvd., 29 Dimitrie Mangeron, 700050, Iasi, Romania, amihai@tuiasi.ro
  - ²Bremen University, Institute Technolgy and Education (ITB), Am Fallturm 1, 28359, Bremen, Germany, asaniter@uni-bremen.de
  ABSTRACT. The Work Based Learning (WBL) pilot stands on a Locally Developed Curriculum elaborated within a partnership consisting of an Educational Institution (Technical high school), Economic operator (Footwear company) and a Public institution (University) and serves as a good apprenticeship model for both, VET providers and footwear companies. The goal of this study is to describes the apprenticeship experience and the stages of implementing WBL in Romanian footwear company, namely: selection of apprentices, WBL pilot planning, tutors training on WBL, WBL pilot implementation, and formative quality assurance. WBL pilot programme in Romania was applied at Papucei footwear company and involved three young apprentices from “Ion Holban” Technical College of Iasi with background in Textile and Clothing field. During one year, according to the developed WBL pilot program and guided by previously trained tutors from Papucei and TUIASI, the apprentices followed all the Core Spheres (Cutting, Pre-stitching, Stitching, Pre-lasting, Lasting, Assembly and Finishing) and Peripheral Spheres (Technical Development, Production planning, design and Quality Assurance) specific to industrial footwear manufacturing. The apprentices’ achievements were evaluated by the responsible tutors using the special designed Matrices found in the Manuals developed by ICSAS to support tutors involved in WBL process. The entire apprenticeship experience was then investigated and evaluated by relevant stakeholders using SWOT analysis to highlight the strengths, weaknesses, opportunities and threats.
  
  KEY WORDS: apprenticeship, Work Based Learning (WBL), industrial footwear manufacturing, VET system, locally developed curriculum
  Read article
THE BEHAVIOR OF SHEEP LEATHER PARCHMENT TO ARTIFICIAL AGEING
- Pages 313-322
  Lucreția MIU^{1, *}, Elena BADEA^{1, 2}, Claudiu ŞENDREA¹, Maria-Cristina MICU¹, Simona Maria PĂUNESCU¹, Iulia Maria CANIOLA¹
  - ¹INCDTP – Division: Leather and Footwear Research Institute, 031215 Bucharest, Romania, lucretia.miu@icpi.ro
  - ²Department of Chemistry, Faculty of Sciences, University of Craiova, Calea Bucureşti 107 I, 200585 Craiova
  ABSTRACT. Parchment used for restoration, book binding and art requires special performance on physical-chemical, organoleptic and aesthetic characteristics, but also good long-term stability. In this sense, the parchment is ecologically processed, with features that ensure firmness, fullness, light resistance, dimensional stability, thermal stability, malleability, flexural/pressure bending resistance. For a good behaviour in time and to artificial ageing, it is found that in the case of parchments made/obtained from sheepskin, the fat or volatile matter content must be as low as possible. The parchment with these qualities allows for the creation of new covers or historical replicas, complements for the integration of old covers, hot and/or cold stamping modelling, incision, entrainment, deposition of gold and silver foil, colouring and decoration with pigments and dyes. Some niche areas such as book bindings and art require a dedicated craftsmanship that promotes the survival of artisanal forms of production and the perpetuation of local creativity and identity. The parchments have undergone artificial ageing treatments based on the concomitant action of temperature and relative humidity for up to 16 days. Chemical (volatile matter, extractable substances, total ash, total nitrogen, dermal) and physical-chemical (measurement of colour variation and shrinkage temperature) analyses were performed to evaluate colour parameters and collagen hydrostability. The fat content of the parchment leads to oxidation reactions that cause the bathochromic effect, closing the colour, but also the deterioration over time of the fibrillar structure by depreciating the contraction temperature.
  
  KEY WORDS: parchment, heritage object, colour change
  Read article
BIODEGRADABLE POLYMERIC COMPOSITE BASED ON RECYCLED POLYURETHANE AND RUBBER WASTES: MATERIAL FOR GREEN SHOE MANUFACTURING
- Pages 323-331
  Laurenţia ALEXANDRESCU*, Mihai GEORGESCU, Maria SÖNMEZ, Mihaela NIȚUICĂ
  - INCDTP – Division: Leather and Footwear Research Institute, 93 Ion Minulescu st., 030215 Bucharest, Romania, laurentia. alexandrescu@icpi.ro
  ABSTRACT. This paper presents the process of obtaining biodegradable polymeric composites based on post-consumption thermoplastic polyurethane and post-consumption vulcanized rubber waste, in various ratios (5, 10, 20, 30, 50%), cryogenically ground to min. 100 nm, and maleic anhydride grafted polyethylene as compatibilizer between the two phases. This composite will be formed into a low-density product, with low cost, recovery and reuse of waste, containing post-consumption polymers, and last but not least, biodegradable. The methodology for making the new materials involves the following steps: sorting waste, grinding, functionalization and compounding. These operations are easy to manage and do not involve new equipment. Compounding, the most important operation, will be carried out on a corotating twin-screw extruder-granulator with the possibility to adjust parameters such as temperature and speed depending on the material, having a screw ratio (L/D-35). The tested biodegradable composites were characterized structurally and physico-mechanically. Waste transformation (ground and functionalized) into new value-added products will lead to remarkable improvements in the life cycle of raw materials and the responsible use of this waste, contributing to sustainability, improving eco-efficiency and economic efficiency and reducing the “pressure” of waste on the environment.
  
  KEY WORDS: biodegradability, polymeric composite, post-consumption, green footwear
  Read article